1804

President Jefferson appoints Isaac Briggs Surveyor General of Louisiana Purchase

1806

Quaker Richard Thomas provides for manumission of 112 slaves; they become nucleus of black community Cincinnati, near Brinklow; Thomas Moore becomes Chief Engineer for C&O Canal and National Road west.

1808

Brookeville Academy enrolls boy students; receives formal State charter in 1815

1809

Town of Triadelphia laid out by brothers-in-law Caleb Bentley, Thomas Moore, and Isaac Briggs, all husbands of Brooke daughters. They establish a cotton mill

1812

St Bartholomew's Church (Episcopal), successor to the 1758 Chapel of Ease, established on Hawlings River; later moves to Laytonsville

1814

President Madison, fleeing invading British in War of 1812, spends night at home of Caleb and Henrietta Bentley in Brookeville

1816

Using brick fired on the site, Friends erect a Meeting House, the county's largest church at the time; Sandy Spring Post Office established at Harewood, James P. Stabler postmaster

1819

Caleb Bentley and James P. Stabler open general store at site of today's Sandy Spring Store; Sandy Spring becomes a village; Fair Hill Boarding School opens in Mechanicsville (today's Olney), operates for 46 years; Benjamin Hallowell begins teaching at Fair Hill Friends School in Mechanicsville

1822

Sandy Spring blacks establish Sharp Street Church (Methodist)