Seven California cities or regions were among the 50 most-infested states in the nation.

Rats and mice are quite common in cities, and Denver is no exception. According to a nationwide pest control company, the Mile High City was one of the most "rodent-infested cities" in the country last year.

One Michigan city was ranked in the top 50 most rodent-infested cities in the nation. – One Michigan city was ranked in the top 50 most rodent-infested cities in the nation. The most rodent-infested city is—you guessed it—New York City, followed by two Californian cities, San Francisco and Los Angeles. Detroit ranked #16 on the list.