It was raised to city status on August 1, 1954 by the merger of the town of Iiyama with neighboring villages of Akitsu, Tokiwa, Yanagihara, Tozama, Kijima and Zuiho.

Iiyama has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 16 members.

The economy of Iiyama is primarily agricultural with emphasis on rice, asparagus, mushrooms and potatoes.

Seasonal tourism to ski resorts and hot springs also make a major contribution.

[5] The TV and electronics manufacturer Iiyama was founded in the city in 1972, although, after a series of mergers, the company is no longer headquartered there.