During the American Civil War the Battle of Monocacy (Monocacy, Battle of) (July 9, 1864) was fought to the south of Frederick. Although Confederate forces were victorious, they were delayed there long enough for Union reinforcements to reach Washington, D.C. (Washington) Following the battle, the city paid a $200,000 ransom to Confederate General Jubal A. Early (Early, Jubal A) to avoid its destruction; the last bond on this debt was not redeemed until October 1, 1951.

The city is an agricultural trading and small manufacturing centre, with several firms in the area specializing in biotechnology. Fort Detrick, site of the U.S. Army Medical Research Institute of Infectious Diseases, is also an important part of the local economy. Educational institutions include Hood College (1893), Frederick Community College (1957), and the Maryland School for the Deaf (1867).

Francis Scott Key (Key, Francis Scott), author of “The Star-Spangled Banner,” (Star-Spangled Banner, The) was born nearby and was buried in Mount Olivet Cemetery. Key's brother-in-law, Chief Justice Roger Brooke Taney (Taney, Roger Brooke), who delivered the Dred Scott decision (1857) that made slavery legal in U.S. territories, lived in Frederick; his house (1799) contains Taney and Key mementos. Barbara Fritchie (Frietschie, Barbara Hauer)'s reputed taunting of Confederate General “Stonewall” Jackson's “rebel hordes” marching through Frederick was memorialized in John Greenleaf Whittier's poem “Barbara Frietchie”; her house has been reconstructed as a museum. Inc. 1817. Pop. (1990) 40,148; (2000) 52,767.

city, seat (1907) of Tillman county, southwestern Oklahoma, U.S. With the opening of the Kiowa-Apache-Comanche reservation to settlement in 1901, the community grew up around a stop on the Blackwell, Enid, and Southwestern Railway. Initially known as Gosnell and renamed in 1902 for the son of railroad magnate J.C. van Blarcom, Frederick developed as a shipping point for locally produced grains and produce. Members of the gang of Bonnie Parker and Clyde Barrow (Bonnie and Clyde) were active in the area, robbing the town's bank in 1933. During World War II, Frederick Army Air Field, now the municipal airport, was an important transport centre staffed largely by women pilots. Inc. 1902. Pop. (1990) 5,221; (2000) 4,637.

county, northern Maryland, U.S., bounded by Pennsylvania to the north, the Monocacy River to the northeast, Virginia to the southwest (the Potomac River constituting the border), and the Blue Ridge Mountains (Blue Ridge) to the west. It consists of a piedmont region bisected north-south by the valley of the Monocacy. Parklands include Cunningham Falls State Park and Catoctin Mountain (national) Park, site of the Camp David presidential retreat. The Appalachian National Scenic Trail follows the ridgeline along much of the county's western border. The county was created in 1748 and named for Frederick Calvert, 6th Baron Baltimore. Frederick, the county seat, is located a few miles north of the site of the Battle of Monocacy (Monocacy, Battle of) (July 9, 1864) of the American Civil War.

Principal economic activities are agriculture (corn 【maize】, hay, and dairy products) and manufacturing. Frederick has the largest area of any county in the state. Area 663 square miles (1,717 square km). Pop. (2000) 195,277; (2007 est.) 224,705.