doun County is variously reckoned at 460, 468, 495,
504, 510, 519, 520, and 525 square miles. The approximate accuracy of
any single estimate in this confused assortment can not easily be
determined, none, so far as is known, having been officially
confirmed. Yardley Taylor, who, in 1853, made a most careful survey of
the County, fixed its area at 525 square miles. By far the most
trustworthy authority in this and certain other connections, his
findings have been adopted with little uncertainty or hesitation.

Of this number, 207 square miles lie east of Catoctin Mountain and are
of the upper secondary formation, while the remaining 318 square miles
to the westward are of primitive formation.

The longest line across the County is 35 miles, and extends from the
lower end of Lowe's Island at the old mouth of Sugarland Run, to the
summit of the Blue Ridge at Ashby's Gap; the second longest, 34 miles,
extends from the corner of Jefferson County, West Virginia, at the
margin of the Potomac River below Harpers Ferry, to the corner of
Fairfax County on Bull Run, within half a mile of Sudley Springs in
Prince William County.

Within the limits of Loudoun are included 313,902[16] acres of the
finest farm land to be found in any county of the State. The farms
number 1,948, the average size being 162 acres. They are smallest in
the northwestern portion of the county and of moderate size in the
central portions, the largest occurring in the southern and eastern
portions. In 1900, 1,754, or 90 per cent, were operated by white
farmers, and 194, or 10 per cent, operated by colored farmers.

[Footnote 16: It will be understood that the total land in farms by no
means equals the total area of the County.]

TABLE I.--_Summary by Decades of the Improved and Unimproved
Land in Farms, with per cent of Increase and Decrease._

-------+-----------------------------------+---------------------------------
| Acres of Land in Farms. | Per cent of Increase.
|---------+-----------+-------------+---------+----------+------------
Census | | | | Total | Improved | Unimproved
Year. | Total. | Improved. | Unimproved. | Land. | Land. | Land.
-------+---------+-----------+-------------+---------+----------+------------
1900 | 313,902 | 251,874 | 62,028 | 6.4 | 6.9 | 4.8
1890 | 294,896 | 235,703 | 59,193 | [*]1.3 | 1.4 | [*]11.
1880 | 298,8