The Ridgeland Tower and its corresponding region are directly west of the Central Region of Hyrule (and Hyrule Castle). You are likely to pass through on your way to the Rito Village. The Ridgeland Tower itself is located in the center of a lake. The best method to get there is to use Cryonis.
Of course, it was never going to be that easy. The lake is swarming with Lizalfos and Wizzrobes who are all too eager to attack you while you are on your little ice cubes. Your Bows can only reach so far, so your best bet is to sneak through. If you want to defeat the enemies, try to keep fights one-on-one so you are not overwhelmed.
The Tower itself is a straightforward climb. As usual, you can skip Cryonis and the lake entirely if you happen to possess Revali's Gale. But if, like us, you were unlocking this Tower on the way to the Rito Village, you will have to do this the hard way.