Chestnut Hill Reservoir is a reservoir created in 1870 on existing marshes and meadowland to supplement the city of Boston's water needs. It is surrounded by Chestnut Hill, a neighborhood which consists of parts of Boston, Brookline, and Newton. The reservoir, though, is located entirely within the city limits of Boston. A 1.56 mile jogging loop abuts the reservoir. Chestnut Hill Reservoir was taken offline in 1978 as it was no longer needed for regular water supply distribution, but is maintained in emergency backup status.