Annapolis Junction is an unincorporated community in Howard County and Anne Arundel County, Maryland,United States.
The lands of Annapolis Junction were first settled around 1650. Provincial Assembly of Maryland member and Anne Arundel County Justice Colonel Henry Ridgely (1645-1710) surveyed the land around Annapolis Junction and nearby Savage Mill in 1685 naming the tract "Ridgely's Forrest". Annapolis Junction was established as a rail junction on the north-south mainline of the Baltimore and Ohio Railroad(B&O) when the tracks of the Annapolis and Elk Ridge Railroad terminated here in 1840. Since this provided a rail route to Annapolis from Washington and Baltimore via the B&O, it was, therefore, a junction to Annapolis. On August 26 1844 the Annapolis Junction post office opened.On May 1, 1844, in a small wooden building along the railroad tracks, the first practical news telegram was sent from Annapolis Junction. The message, from Alfred Vail to Samuel F. B. Morse, announced that the Whig Party candidate would be Henry Clay, and his running mate would be Theodore Frelinghuysen. The candidates left Annapolis Junction by train, and arrived in Washington to find the news was already being announced in the city by the local papers.Annapolis Junction is the site of William Bowie's home Grassland, built in 1853.