There's a stretch of pretty much unbroken city from Ogden through and past Provo, with SLC being in the middle. Outside of that stretch, usually called the Wasatch Front (after the Wasatch range of mountains) there's really not a whole lot. Logan is just south of the Idaho border, and St George just north of the Arizona border; those are probably the next "big contenders" for cities, with St George having a real boom over the last five years or so that's projected to continue for a while yet.
Other Utahns could probably give you more precise numbers.