From Thomas Jefferson Encyclopedia
To keep ice for the plantation, Thomas Jefferson constructed an ice house.  In the winter of 1802-1803 the summer's harvest of wheat was safely stored in barrels and barns. Monticello overseer Gabriel Lilly had to wait for freezing temperatures before he could harvest his next crop: ice from the Rivanna River. Every available neighborhood wagon was assembled to bring ice from the river to the newly constructed ice house on the mountaintop. Jefferson, monitoring the operation from Washington, recorded it took "62. waggon loads of ice to fill it," and cost $70 for the hire of wagons and food and drink for the drivers.
This was not Jefferson's first ice house. He had had one built and filled at the President's House the year before. Until then he did without ice in the country and bought a weekly supply in the city. In Philadelphia in 1792, he actually subscribed to a summer ice service. The vaulted cellar of James Oeller's Chestnut Street hotel provided a daily supply of ice for a shilling a day. A Wiltshire clothier stopped at Oeller's for a refreshing round of punch, and thought fit to record that it was "brought to us with a lump of ice in each glass." He was not the last Englishman to marvel at the American ice-cube habit.
Jefferson had taken notes on ice houses in Italy and Virginia before he undertook construction of his own. He placed it on the coldest side of the house, under the North Terrace. His drawings show a cylinder sixteen feet below ground level and six feet above it, with openings at the top "left only 9. I[nches] square that a person may not get in at them."
That specification indicates that more than ice was in the ice house. "Dishes of butter, cold dressed provisions, salads, etc." were kept in Oeller's ice cellar and Monticello's may have been used in a similar way. The preservation of butter and fresh meat was Jefferson's main concern. It would be "a real calamity" if the ice house were not filled, he wrote his overseer in 1809, "as it would require double the quantity of fresh meat in summer had we not ice to keep it."
Then there were the less critical uses for the ice crop, such as the making of ice cream or chilling of wine. Jefferson liked to tell of his efforts to elicit expressions of astonishment from the Indian delegations that visited him at the President's House. He succeeded only once-when wine bottles in ice-filled coolers were placed on the table in July.
After viewing the Italian ice house, Jefferson had recorded that "snow gives the most delicate flavor to creams; but ice is the most powerful congealer, and lasts longest." We know that in 1815 the ice lasted until October 15.
The day before Christmas in 1813 Jefferson wrote: "Filled the ice house with snow." As ice house at the river took over the primary role and the mountaintop cellar now became the "snow house"-and Monticello may be here today because of it. In the spring of 1819, the North Pavilion caught fire. As Jefferson reported to a friend, "our snow house enabled us so far to cover with snow the adjacent terras which connected it with the main building as to prevent it's affecting that."
Primary Source References
1787 April 23. (Jefferson-Tour through Southern France). "The Ice-Houses at Rozzano are duge about 15. f. deep and 20. f. diameter and poles are driven down all round. A conical thatched roof is then put over them 15. f. high. Pieces of wood are laid at bottom to keep the ice out of the water which drips from it, and goes off by a sink. Straw is laid on this wood, and then the house filled with ice always putting straw between the ice and the walls, and covering ultimately with straw. About a third is lost by melting. Snow gives the most delicate flavor to creams; but ice is the most powrful congealer, and lasts longest. A tuft of trees surrounds these ice house."
1813 December 24. "Filled the ice house with snow."
1817 January 20. "Filled the Ice house at the river with ice."
1817 March 13. "Filled the Snow house here with snow."
1819 May 5. (Jefferson to John Barnes). "In answer to your kind enquiries as to our fire, the loss was confined to the little pavilion which, as you remember, constituted the Northern extremity or wing of my buildings. Our snow house enabled us so far to cover with snow the adjacent terras which connected it with the main building as to prevent it's affecting that."
1823 February 23. (Virginia Jefferson Randolph Trist to Nicholas Trist). "Since I wrote to you last the weather has been that of our severe winters, the thermometer falling once as low as 10. and frequently to 13, 14, and 15 but yet we have not had a snow deep enough to fill the ice house."