1820: Loudoun registers its largest pre-Civil War population, 22,072. Slaves number 5,729, about 25 percent, free Negroes 829, or about 3.7 percent. Of 140 black households, 19, or 13.6 percent, own slaves. The decline in the number of slaves in Loudoun County, because of moral concerns and a large Quaker population, counters the national trend--a 65 percent increase since 1800.

1820: Late in the year, Virginia's General Assembly receives a petition signed by more than 600 residents to create a new county comprising the wealthiest sections of Loudoun, Fauquier and Prince William counties. It would extend from Snickers' Gap to Oatlands on the north, then along the Little River Turnpike (today's Route 50) to the Fairfax County line, then south to Bull Run and west to the Blue Ridge along today's Route 55. Because the finest soils of these three counties would be removed from each county's tax rolls, the legislature tables the petition, the last from this area asking for the formation of a new jurisdiction.

1822: The county government establishes a 229-acre Poor Farm near present-day Unison (then called Union) to house the indigent and mentally ill. With separate quarters for blacks and whites, "inmates" work in exchange for bed and board. Gradually, the farm grows to 424 acres and is a regular meeting place (with sumptuous dinners) for post-Civil War boards of supervisors. With the opening of a regional facility at Manassas, the poor house closes in 1946. Today it is a bed-and-breakfast, still known as the Poor House.

1823: The fifth president, James Monroe, establishes a part-time residence a few miles south of Leesburg at Oak Hill, which was designed by Thomas Jefferson and built under direction of James Hoban, designer of the White House and architect of the U.S. Capitol. At Oak Hill that autumn, the president drafts the Monroe Doctrine, warning European powers not to interfere in the Western Hemisphere's affairs. President Monroe's last public office will be that of Aldie area justice of the peace. Two other U.S. presidents--James Buchanan and John F. Kennedy--will have part-time Loudoun addresses.

1825: On his farewell visit to the United States he helped to create, the Marquis de Lafayette visits Loudoun in August. The Revolutionary War hero is feted by President Monroe at Oak Hill, Ludwell Lee at Belmont and Thomas Ludwell Lee's widow, Fanny Carter Lee, at Coton, and an estimated 10,000 people gather at Leesburg--an honor unmatched for any foreign dignitary.

1828: Lovettsville, market town of the German Settlement, takes the name of Quaker developer David Lovett, who began selling lots in 1820. The General Assembly, in its final act of establishing trustees for a Loudoun town, sanctions the hamlet in 1836. Its churches hold bilingual services through the 1830s.

By 1831: Loudoun has 75 schools for 900 poor children, and they are open for only 70 days. In 1846, Virginia passes a bill giving counties the option of establishing public schools if two-thirds of the voters agree. Six counties, including Culpeper, vote for public education. The others, Loudoun included, reject it, fearing that the schools would admit free blacks.

1831: Baptists, which make up one-third of the county's populace, diverge on whether there should be paid clergy, music during services, missionaries and Sunday school for children rather than having them sit through hours of preaching. The "Old School" does not hold to these ideas; the "New School," which eventually predominates, does. New Schoolers build their own churches at North Fork and Ebenezer, separated from the meetinghouses of the Old Schoolers--soon to be termed Primitive Baptists--by shared graveyards. All four churches, unique to Virginia, still stand in pristine settings.

1834: The Leesburg and Snickers' Gap Turnpike completes its right of way, today's old Route 7 through Hamilton, Purcellville and Round Hill. Wagons from the Shenandoah Valley make the trip to Washington in three days, from Loudoun in two. The road establishes a corridor of commercial growth through the Loudoun Valley.

1834: The Chesapeake & Ohio Canal, heir to the Patowmack Company canal, reaches Harpers Ferry, W.Va. From seven Loudoun ferry docks and other landings, farm produce aboard flatboats crosses the Potomac to canal outlets. On barges, the produce reaches Washington in a day. The competing Baltimore & Ohio Railroad arrived at Point of Rocks, Md., in 1832 and will arrive in Harpers Ferry in 1836. There it will connect with a rail line to Winchester. Produce from the lower Shenandoah Valley and Loudoun farms near the Potomac are in Baltimore in a few hours. Turnpikes, all of them toll roads, are the losers.

1835: In Joseph Martin's Gazetteer, Yardley Taylor, Quaker geographer, horticulturist and surveyor, presents Loudoun to the world with glowing write-ups of bustling villages and prosperous countryside. Little wonder, for land in the western county sells for more than $20 a raw acre, a price matched in Virginia only by upper Fauquier.

1835: Farmers wear overcoats and gloves in the wheat fields during a fall cold wave preceding the first recorded visit of Halley's comet in December and January. The year 1859 will be remembered as the "Year Without a Summer"; a June 4 frost is the latest on record. Upon Halley's second visit in April-May 1910, snow lingers atop the Blue Ridge through June.

1836: Richard Henderson, Loudoun's first commonwealth's attorney, contends it is virtually impossible to prosecute free blacks who have come to Loudoun from other states. (Virginia law has made such migration illegal since 1793.) He petitions the state unsuccessfully to remove all free blacks to "the Western coast of Africa." Free Negroes make up more than 5 percent of the county's population, and they take jobs from whites.

1836-1846: Margaret Mercer, daughter of former Maryland Gov. John Francis Mercer, uses proceeds from her preeminent "school for young ladies" to free her slaves and pay for their passage to Liberia. After her death, Virginia Kephart continues the school until 1861, a record for a girls' school in Loudoun until Foxcroft School celebrates its 26th anniversary in 1940.

By 1840: Agricultural machinery has made an impact. Two Fauquier County inventions--Stephen McCormick's detachable cast-iron plow and Benjamin O'Rear's thrasher--speed tilling and harvesting. Grain separators and horse-powered assemblages are fixtures on many large farms. Mills have several burrs to grind different grains and corn at the same time. Some mills card wool and have circular saws to cut timber.

1844: Quaker Samuel Janney writes a series of anti-slavery polemics in the Alexandria Gazette. He argues for the "superiority of free labor" and proposes an end to the domestic slave trade. He writes a friend: "I think public sentiment advancing here in favor of emancipation. There are many opposed to slavery than is generally supposed, but they are afraid to avow their sentiments."

1845: The two largest Methodist congregations in Loudoun divide over slavery. In Leesburg, the Northern Methodists, opposed to slavery, move out of the congregation's 1785 church to a church on Liberty Street, where blacks hold services in the late 1850s. (The building, almost forgotten, stands today.) In Middleburg, the breakaway pro-slavery Methodists leave that congregation's 1829 Asbury Church and move to the present 1857 church. Blacks worship at Asbury during the Civil War.

1847: Loudoun hosts its first international sporting event as the British Isles' Bob Caunt challenges the U.S. champion, Irish-born Yankee Sullivan, for the world heavyweight boxing crown. Although it was slated for Harpers Ferry, U.S. armory officials fear the usual post-match riot and move the fight to nearby Dixie Bottom. Sullivan wins in seven, and the melee is quenched by a downpour.

1850: The population, at 22,679, remains stable; 5,641, or about 25 percent, are slaves; 1,357, or about 6 percent, are free Negroes, a decline of 7 percent since 1840. Loudoun registers its largest pre-Civil War black population.

1850: Indicted by a grand jury for a "calculated" effort to "incite persons of color to make insurrection or rebellion" and for remarking that slave owners "had no right of property in their slaves," Samuel Janney is tried in June. He is acquitted on both counts.

By 1851: The Loudoun County Agricultural and Chemical Institute, Virginia's first college-level agricultural school, opens near Aldie. Benjamin Hyde Benton, who previously taught school at his home, New Lisbon (now Huntlands near Middleburg), and who defied state law by teaching his slaves to read and write, heads the institution. It will survive until the Civil War. Its magnificent four-story quarters, constructed by Harmon Bitzer, still stands and is known as Institute Farm. Since 1916, it has been headquarters of the National Beagle Clubs.

1852: A three-deck wooden bridge at Point of Rocks is the first permanent span linking Loudoun to Maryland. One deck carries passengers, the second vehicles and the third horse-drawn cars on a narrow-gauge railway. An 1850 covered bridge at the site had been destroyed by Potomac flooding. The cars carry pig iron, mined and smelted at the Potomac Iron Furnace works. The furnace's iron pits and charcoal paths yet remain.

1852-1857: The Manassas Gap Railroad grades the right of way for its Loudoun Branch, extending from the Manassas Gap main line, west and north to Purcellville. The railroad was to reach Harpers Ferry, to draw Baltimore-bound produce back to Virginia. Tracks are laid as far as Arcola and, possibly, Oak Hill, but the line is abandoned, possibly because of the severe Depression of 1857. Confederates remove the tracks when they abandon their perimeter around Washington in fall 1861.

1854: After five years of construction, with nine locks, four canals and four dams, the Goose Creek Canal extends nine miles from Evergreen Mills near Leesburg to the Potomac, where it connects to the Chesapeake & Ohio Canal. To prove that the works are navigable during this dry summer, slaves drag a boat to the mills, where, submerged, it now rests. The canal may have been used through the 1880s. Its locks, some in a near-pristine state, are among Loudoun's finest reminders of the past.

1857: Loudoun's second Potomac bridge, a 1,568-foot-long covered wooden affair, links Berlin, Md., (which became Brunswick in 1890) and the Baltimore & Ohio Railroad with the German Settlement. Trending south to Hillsboro and Purcellville is the Berlin Turnpike (now Route 287)--whose toll houses are still in place. Another toll road--the current Harpers Ferry Road (Route 671)--bonds Hillsboro with Harpers Ferry. Crops from Between the Hills and the rich Loudoun Valley move rapidly to railroad and canal.

1857: A broadside accuses Yardley Taylor, who now carries the U.S. mails, of being "Chief of the abolition clan in Loudoun" and of harboring runaway slaves--illegal under the 1850 Fugitive Slave Act. The Underground Railway, assisting escaping slaves, is active in the predominantly Quaker Loudoun Valley.

1859: Pennsylvania refuses to extradite Daniel Dangerfield, an escaped slave who worked at the Aldie Mill. Sentiment is strong in eastern Loudoun for his return. The opposite is true in much of western Loudoun.

1860: The Alexandria, Loudoun & Hampshire Railroad, first to carry scheduled passengers and freight to Loudoun, reached Sterling in 1859. The village was then called Buchanan, named for President James Buchanan, who had a summer home there. Upon the railroad's arrival at Leesburg, in May 1860, the town's newspaper waxes: "We are now hitched to the rest of the world, about an hour and a half to two hours' travel from Alexandria and Washington."

CAPTION: The Poor Farm was established in 1822 to house the indigent and mentally ill. Today, it's still known as the Poor House but serves as a bed-and-breakfast.

CAPTION: Loudoun rolled out the red carpet for the Marquis de Lafayette, above, in 1825. President Monroe was his host at Oak Hill, below.

CAPTION: Yardley Taylor gave Loudoun some good publicity with an 1835 write-up in a gazetteer. In 1857, he would be accused of illegally harboring runaway slaves.

CAPTION: The Alexandria, Loudoun & Hampshire Railroad finally reached Leesburg in 1860.