Baird Montgomery County photograph collection

Montgomery County, Maryland was formed as a political unit in 1776, having formerly been a district of Frederick County, which had grown unmanageably large in the face of increasing war activity in the region. Named for General Richard Montgomery, the county originally encompassed lands (including Georgetown) that later became part of the District of Columbia. The county seat was established at what later became Rockville, which took its name from Rock Creek.

It was at Brookville in Montgomery County that President Madison and members of his cabinet took refuge when the British captured Washington and burned public buildings in 1814. It was also near Brookville that gold was reportedly discovered in 1849 on Samuel Ellicott's farm. Gold was believed to be present in the Potomac area, and was discovered again during the Civil War by troops camped in the vicinity of Great Falls.

In 1828, construction of the Chesapeake and Ohio Canal was begun with President John Quincy Adams breaking ground in Georgetown. The canal's purpose was to provide a trade route over the Appalachian Mountains to the Ohio River Valley and the mid-west, since the Potomac was the only river in the East to bisect the Appalachian mountain barrier. By 1850, the canal reached its conclusion in Cumberland, Md.

Great Falls is a natural landmark where the Potomac River holds a series of rapids interspersed with 20 foot waterfalls, falling a total of 76 feet over a 3500 feet distance. It has long been a popular destination site for visitors from near and far, viewable from Maryland or Virginia. The head of Great Falls is the site of the Aqueduct Dam which is the intake for the District of Columbia's water supply system, for which construction was begun in 1853. Designed and overseen by Montgomery Meigs, the system called for diversion of Potomac River water into a 12-mile brick conduit, with gravity and pumping stations conveying the water to reservoirs for pumping into city pipelines. The complex infrastructure needed to support this endeavor included 11 tunnels and 6 bridges in addition to the conduit, pump stations, reservoirs and pipelines. The Chesapeake and Ohio Canal was an important route for bringing to the construction sites the large quantities of materials needed: cast iron, sand, concrete, brick, and sandstone.

By the mid-1800s, Montgomery County became a prosperous farming area. The success of farming in the region is attributed to the use of Peruvian guano, imported by the Quakers of Sandy Spring in 1844, as a fertilizing material. The area remained predominantly agricultural until about 1940. In 1874, the Montgomery County Agricultural Society was formed, holding annual Fairs in Rockville which featured agricultural achievement and home arts competitions, and horse races.