Lansdowne is a borough in Delaware County, Pennsylvania, United States. It is essentially a residential suburb of Philadelphia. Population in 1900, 2,630; in 1910, 4,066; and in 1940, 10, 837. The population was 11,044 at the 2000 census. Lansdowne is located 5 miles southwest of Philadelphia. Lansdowne apartments for rent comparison page shows most up to date rent information on Lansdowne apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.