Gabriel Lilly was an overseer at Monticello from 1800 to 1805. George Granger, Monticello's only enslaved overseer, died on November 2, 1799, so it is possible that Thomas Jefferson hired Lilly soon after Granger's death.
Lilly had responsibility for the nailmaking operation and for supervising enslaved men working at non-agricultural tasks such as building an ice house, digging a canal for the Shadwell mills, and constructing the Shadwell toll mill. He had very little to do in the way of agricultural management, since Jefferson leased out the farm fields to John Craven. Jefferson knew of Lilly's harsh treatment of the enslaved people he supervised but placed greater value on his ability to achieve results, telling his son-in-law: "certainly I can never get a man who fulfills my purposes better than he does."  
In 1805, Lilly asked for a raise that Jefferson was reluctant to provide. Soon thereafter, Lilly moved to Kentucky.
1800. "Lilly" noted as Monticello overseer 1800 to 1805.
1800 December 22. (Richard Richardson to Jefferson). "I Carryed Mr lilley to the Shop this morning and told the Boys they was to Be under his direction and Joe to say when their nails was made tow Big or too small with this arangement they will go on till I see Mr powel or hear wheather he is a Comeing. if he does not I will Return direcly after Christmas ...."
1801 January 3. (Thomas Mann Randolph to Jefferson). "Lillie has failed in hiring, except one single laborer; they could not be had under 25.£ any where & difficultly for that: his exertions were what might have been expected of him but the great price in our neighbourhood & the impossibility of persuading them to come up from below, which the facility of hiring every where makes allways a condition, have rendered them vain. ... having abandoned all hope of Lillies hiring hands I directed him to take the lads from the shop, leaving 3 full fires of the boys with Burwell at their head. ... I have directed Lillie to look himself to those who remain at the nailery, for their work .... It was absolutely necessary to do something without waiting to consult you for the Nailery was all in confusion, Lillie without a hand and Craven in despair because the work to be done for him was standing still."
1801 January 16. (Jefferson to Martha Jefferson Randolph). "[I]t gave me real joy to learn that Lilly had got a recruit of hands from mr Allen; tho' still I would not have that prevent the taking all from the nailery who are able to cut, as I desired in mine of the 9th. as I wish Craven's ground to be got ready for him without any delay."
1801 January 23. (Jefferson to Thomas Mann Randolph). "I forgot to ask the favor of you to speak to Lilly as to the treatment of the nailers. it would destroy their value in my estimation to degrade them in their own eyes by the whip. this therefore must not be resorted to but in extremities. as they will be again under my government, I would chuse they should retain the stimulus of character. after Lilly shall have compleated the clearing necessary for this year for mr Craven, I would have him go on with what will be wanting for him the next year .... P.S. when I come home I shall lay off the canal, if Lilly’s gang can undertake it. I had directed Lilly to make a dividing fence between Craven’s fields at Monticello, & those I retain. ... I hope Lilly keeps the small nailers engaged so as to supply our customers in the neighborhood, so that we may not lose them during this interregnum."
1801 January 29. (Jefferson to Thomas Mann Randolph). "I am very glad indeed to find that Lilly has got so strong a gang, independant of yours & the nailers. ... I should be glad mr Lilly or mr Dinsmore would count the faggots on hand, & inform me of the quantity by return of post; as I have forgotten the state of the supplies on hand, when I left home."
1801 June 13. (Thomas Mann Randolph to Jefferson). "Lillie had begun to work on the Canal & was going on with much spirit but has been compelled by Cravens discontent to return to the new clearing to collect & burn every scattered chunk & grub up every neglected bush in it, alltho' it was allready done in a manner much better than usual."
1801 July 16. (Jefferson to Martha Jefferson Randolph). "... the inclosed letter to mr Craven ... will secure you all the resources for the house which he can supply. ... Lilly has before recieved orders to furnish what he can as if I were there."
1801 July 25. (Martha Jefferson Randolph to Jefferson). "[Y] our other commissions shall be faithfully executed with regard to Lilly"
1802 January 4. (Jefferson to Thomas Mann Randolph). "[A]s he [Lilly] cannot read, I will pray you to send for him and deliver the letter & money yourself ...."
1802 January 17. (Jefferson to Martha Jefferson Randolph). "P.S. in my last week’s letter to mr Randolph I inclosed one for mr Lilly with 940. D. in it, which I shall be glad to hear got safe to hand."
1802 April 3. (Jefferson to Martha Jefferson Randolph). "I have desired Lilly to make the usual provision of necessaries for me at Monticello, and if he should be at a loss for the particulars to consult with you."
1802 September 28. (Notes on an Agreement with James Walker). "[H]e is to come over, designate to mr Lilly & mr Hope the spot where my small mill is to be built, so as not to be in the way of the large one .... In the spring he is to designate to mr Lilly & mr Hope the spot for the large mill ...."
1803 January 27. (Jefferson to Martha Jefferson Randolph). "I find mr Lilly was to begin filling his icehouse the 21st. we have had no thaw here since that till yesterday, & the river is still entirely blocked up; so that if the weather has corresponded there, I am in hopes he will have got his house full."
1803 February 7. "Inclosed to Gabriel Lilly for waggonage of ice 30. D."
1803 March 25. (Jefferson to James Walker). "I find it to be the opinion of mr Lilly that having hired an extraordinary force for the year he shall be able to compleat the canal for my mill this summer. ... I must therefore ask of you to come over without delay and mark out the site .... if you come before Tuesday I shall be at home, if afterwards apply to mr Lilly my manager here who will send for mr Hope and both of them will attend you on the ground."
1803 April 24. (Jefferson to George Jefferson). "Will you be so good as to procure from old mr Collins or any other faithful seedsman 1. gallon of earliest Frame peas and 2. gallons of Dwarf marrow fats and send them addressed to Gabriel Lilly at Monticello."
1803 June 8. (Jefferson to Thomas Mann Randolph). "[T]here are generally negro purchasers from Georgia passing about the state, to one of whom I would rather he [enslaved youth named Cary] should be sold than to any other person. ... I should regard price but little in comparison with so distant an exile of him as to cut him off compleatly from ever again being heard of. I have written this to mr Lilly and will thank you to advise & aid him in procuring a sale. ... I should indeed be glad to have my toll mill up a season before another, merely to learn people the way to it. but this I am in hopes Lilly will enable me to effect."
1803 September 21. "Settled with Gabriel Lilly and paid him £3–17–3 being the balance due him, but this does not include his wages of the present year which are £50. and £10. extra for overlooking the nailery. From the commencement of the ensuing year he is to have 2. per cent on all the nails sold instead of the £10."
1803 November 27. (Jefferson to Mary Jefferson Eppes). "[M]r Lillie having finished the mill, is now I suppose engaged in the road which we have been so long wanting, & that done, the next job will be the levelling of Pantops"
1803 December 24. (Thomas Mann Randolph to Jefferson). "[S]ome say neither of these elevations [in the canal bottom] extends farther than four or five yards: Lillie believes not more than 10 or 12 feet. ... The Wheel has been set in motion today & moved with great velocity when 4 inches covered. Lillie was determined to grind some grain before night."
1804 January 14. (Martha Jefferson Randolph to Jefferson). "Lilly has been here [Edgehill] to advise with me about Kit—he is now in Charlottesville jail where he passed himself for a negro of Mr Randolph’s, Lilly is afraid to take him out for fear of his going off again he thinks you wished him sold and the money laid out on another, but he says his head was so confused during, and for some time after his illness that he cannot recollect whether you gave him any orders to that effect or not; the result of the conversation however was that if he could get 120 or 25 £ before he could hear from you he should sell him rather than miss the sail but that he would be much obliged to you to let him know by the next post what you wish done with him in case of his not having been able to dispose of him."
1804 January 28. (Jefferson to James Walker). "I must therefore get you to lay off the exact spot for the mill house for mr Hope, furnish him with a plan, and give mr Lilly a bill of scantling, which he will have sawed at the saw mill if compleated, or by hand if not compleated. I presume the sooner the ground is laid off the better, that mr Lilly may commence digging the foundation. possibly he may find blowing to do in it. you can also be so good, when you are there as to advise him about the canal, which has not yet been properly compleated, & the wing dam."
1804 February 26. (Jefferson to Mary Jefferson Eppes). "[W]ill you desire your sister to send for mr Lilly and to advise him what orders to give Goliah for providing those vegetables which may come into use for the months of April, August & september."
1804 November 26. (James Oldham to Jefferson). "The Barbarity that he maid use of with Little Jimmy was the moast cruel. to my noledge Jimmy was sick for thre nights and the moast part of the time I raly thot he would not of Livd, he at this time slepd in the room with me, I informd Lilly the boy was not able to worke and Begd him not to punnish him, but this had no affect he whipd him three times in one day, and the boy was raly not able to raise his hand to his Head?" 
1804 November 30. (Martha Jefferson Randolph to Jefferson). "Lilly was here [Edgehill] a fortnight ago to beg I would write to you immediately about some business of his .... he says you desired him to part with 100 barrels of corn as more than you required, but he says he has got it on very good terms 16 or 16/6 a barrel and that there is not one bushell too much, on account of the heavy hauling he has to do. he says if the horses are not highly fed they will not be able to do the work .... after recieving your letter he went to see Moran about the double payment that had been made, he pretended he knew nothing about it but that he would see Irving and it should be rectified, and that Lilly should hear from him in a fortnight. ... he is obliged to give up K. Smiths negro’s tomorrow as he wished to get all the work possible out of them before they went he deffered going after Irving till their time was out, when he will immediately see him. the man that ran away the first of August has never been recovered. he begged me also to speak particularly to you about John. he is utterly averse to the idea of having any thing to say to him another year. his conduct is such that there can be nothing like honesty or subordination where he is. his wish is that he should be sent off of the plantation and indeed the instances of depravity that he mentioned in him, his art in throwing every thing into confusion, encouraging the hands to rebellion and illness and then telling upon them so as to put Lilly out of his senses allmost, are beyond conception. he says John has frequently created such confusion by his art as to render it impossible to punish the very hands of whom he complained most, and pieces of ill will and mischief to himself inumerable, such as cutting up his garden, destroying his things and once he suspects him of having attempted to poison him. he thinks it necessary for him to be allways upon his guard against him malice. ... Lilly’s business has taken up so much of my time and paper that I have only room to subscribe myself with inexpressible tenderness your affectionate Daughter."
1805 June 5. (Jefferson to Thomas Mann Randolph). "I recieved a letter yesterday from Lilly which gives me great disquietude. he has hitherto been on wages of £ 50. and £ 10. additional for the nailery. he writes me that he cannot stay after the present year for less than £ 100. certainly I can never get a man who fulfills my purposes better than he does: and if a moderate advance, as from 60. to £ 75. would have sufficed, I would have given it. but to £ 100. is a larger jump than I am willing to take if I can find another who will answer my purposes. do you know, or can you recollect one who would, and who could be got on Lilly’s present allowance? I do not wish the least intimation of this matter to any mortal; and shall withold answering Lilly till I hear from you."
1805 June 5. (Jefferson to John Strode). "The person [Lilly] whom I have there at present is at the wages of £.60. & the ordinary allowance of pork & corn for his family. he is as good a one as can be. but I yesterday recieved notice from him that unless I would raise his wages to £100. he could remain only this year. this is so great a jump, that if I can get another worthy of confidence, I think to do so."
1805 June 16. (Thomas Mann Randolph to Jefferson). "Lillie has so much understanding activity and perseverance that he could superintend the culture of one in the best manner with the aid of his Wifes son who lives with him and at the same time manage the nailery and direct any hired force you might chuse to employ for jobs to as much advantage as at present. So doing he would earn his present wages and deserve a liberal share of what he made besides."
1805 August 21. "Bought a negro woman Lucretia Jame’s wife, her 2. sons John & Randall and the child of which she is pregnant, when born, for £180. of which £100. to be paid before his [Lilly's] departure & the residue a twelvemonth hence."
1805 October 6. (Jefferson to Daniel Bradley). "[M]y informant says he [runaway slave James Hubbard] confessed at once the truth of his case, that he had three passes which he said had been given him by the son of mr Lilly my manager. ... it would be important for me to recieve the passes immediately because mr Lilly sets out on Thursday for Kentucky, & if he can get the passes into his hands before he goes I am sure he will probe the forgery to the bottom."
1805 November 14. (Jefferson to George Jefferson). "Mr. Freeman my manager at Monticello in the place of Lilly being new in the business, has improperly applied to you for nail rod."
1806 Fall Memorandum. (Jefferson to Edmund Bacon). "I allow them [slaves] a best striped blanket every 3. years. mr Lilly had failed in this. but the last year mr Freeman gave blankets to one third of them."
1806 May 24. "Recd. by TMRandolph from Gabriel Lilly 1.375 the balance due me at his departure."
1806 June 28. (Jefferson to John Holmes Freeman). "I have recieved an account from mr Higginbotham, by which I find that mr Lilly has left me a heavy sum for dealings to be paid there. this will render it indispensably necessary to push the nailery with all possible force."
931 Thomas Jefferson Parkway
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