The Peaks of Otter are three mountain peaks in the Blue Ridge Mountains, overlooking the town of Bedford, Virginia. These peaks are Sharp Top (3862 feet), Flat Top (3994 feet), and Harkening Hill (3372 feet).
In the fall of 1815, Thomas Jefferson, Francis Walker Gilmer, and José Correia da Serra left Poplar Forest to measure the elevation of the Peaks of Otter. Jefferson returned later in the year and marked out a mile long base along the Otter River with his Gunter's chain, and then with his theodolite took some angles from the summit of Sharp Top. Jefferson returned to Poplar Forest and, using trigonometric calculations, computed the elevation of the peaks.
Primary Source References
c. 1781. "The height of our mountains has not yet been estimated with any degree of exactness. ... The mountains of the Blue ridge, and of these the Peaks of Otter, are thought to be of a greater height, measured from their base, than any others in our country, and perhaps in North America."1
1815 October 12. (Jefferson to Alden Partridge). "[I]t came opportunely, as I was about making enquiries for the height of the White mountains, of N. Hampshire, which have the reputation of being the highest in our Maritime states, and purpose shortly to measure geometrically the height of the Peaks of Otter, which I suppose the highest from their base, of any on the East side of the Missisipi, except the White mountains, and not far short of their height if they are but of 4885. feet. ... I will do myself the pleasure of sending you my estimate of the Peaks of Otter, which I count on undertaking in the course of the next month."2
1816 January 2. (Jefferson to Alden Partridge). "I am but recently returned from my journey to the neighborhood of the Peaks of Otter .... [W]hen lately measuring trigonometrically the height of the peaks of Otter ... I very much wished for a barometer, to try the height by that also. but it was too far and too hazardous to carry my own, and there was not one in that neighborhood. On the subject of that admeasurement, I must premise that my object was only to gratify a common curiosity as to the height of those mountains, which we deem our highest, and to furnish an à peu près, sufficient to satisfy us in a comparison of them with the other mountains of our own, or of other countries."3
1816 August 18. (Jefferson to George Flower). "[O]n your return to Philadelphia I would recommend your passing along the valley between the blue ridge & North mountain, that is to say by the Peaks of Otter, Natural bridge, Staunton, Winchester Harper's ferry, Frederictown & Lancaster. you will thus have seen the two by far most interesting lines of Country of this state."4