Olney, a census-designated place and an unincorporated area of Montgomery County, Maryland, U.S., is located in the north central part of the county, twenty miles (32 km) north of Washington, D.C. It was largely agricultural until the 1960s, when growth of the Washington suburbs led to its conversion into a mostly residential area. As generally defined, Olney had a total population of 31,438 in the 2000 U.S. Census. In July 2007, Money magazine ranked Olney as 17 (the highest ranked town in Maryland) out of the top 100 in its "America's Best Places To Live" edition.