Bloomington is a census-designated place in San Bernardino County. What exactly is a census-designated place? This is a legal distinction between cities, which are incorporated under states' laws, and a population that lives in one area identifiable by a name, like Bloomington. Cities have centralized governments that have elected officials. This isn't present in Bloomington, among other differences.
While this is an important distinction on a legal level, it is a minor one for renters in Bloomington. The CDP is a fantastic place for homes for rent, given its southern Californian location and proximity to the nearby cities of San Bernardino, Fontana, Colton and Rialto. Bloomington is only an hour east of Los Angeles, and is also near the Angeles National Forest and the San Bernardino National Forest. Families living in Bloomington can have all the small-town atmosphere with the amenities of the nearby big cities.