Simplify the following text for a Grade 9 native English-speaking person.
Original: Cranbrook is located in the southeastern and the East Kootenay region of British Columbia .
Simplified: Cranbrook , British Columbia is a city in southeast British Columbia , located on the west side of the Kootenay River at its confluence with the St. Mary 's River , It is the largest urban center in the region known as the East Kootenay .