Isehara (伊勢原市, Isehara-shi) is a city located in central Kanagawa Prefecture, Japan. As of June 2012, Isehara had an estimated population of 101,052 and a population density of 1,820 persons per km². The total area was 55.52 km².

The area of present-day Isehara city was part of several large shōen in Sagami Province during the Kamakura period. During the Edo period, it was nominally part of Odawara Domain, although large portions were tenryō territory controlled by the Shogun in Edo through various hatamoto. After the Meiji Restoration and with the establishment of the district system in 1878, the area came under the control of Ōsumi District (大住郡, Ōsumi-gun), Kanagawa Prefecture and became Isehara town on April 1, 1889. On March 26, 1896, Ōsumi District and Yurugi District were merged to form Naka District. The town began to experience rapid growth after the opening of Isehara Station on the Odakyu Electric Railway on April 1, 1929. On December 21, 1954 the town expanded through merger with neighboring Oyama Town and three villages. Its area expanded further on September 30, 1956 through annexation of a portion of neighboring Okazaki village. Isehara gained city status on March 1, 1971.

Isehara is located in the hilly center of Kanagawa Prefecture. A large portion of the city is within the Tanzawa-Ōyama Quasi-National Park.

Surrounding Municipalities

• Atsugi
• Hadano
• Hiratsuka