Jamnagar (jäm´nəgər), city (1991 pop. 381,646), Gujarat state, W central India. A port on the Gulf of Kachchh, which is an arm of the Arabian Sea, Jamnagar has naval and aeronautical schools. It is a transportation hub, with road, rail, and air transport. A radium institute is also in the city. Jamnagar is a district administrative center known for its silk, embroidery, and marble. There are cotton-textile mills and manufactures in cement and pottery.