There are about 5 branches of Mariscos Chihuahua scattered around Tucson, but our favorite remains the original, the Grande street location west of I-10.
Mariscos Chihuahua is as authentic of a Mexican food place as it gets, in it's teeny little location in a Mexican neighborhood. That the Mexican border is actually about 75 miles down the road is a mere formality, you are definately in Mexico here!
This restaurante serves only seafood (and booze), so be in the mood for fish or shrimp when you come here. In the evenings you may well have to wait to be seated, but some cheap strong margaritas will help ease the pain.
The only dish my husband and I ever get here is called Shrimp culichi. It is a strange looking concoction but ABSOLUTELY DELICIOUS! It may be best described as a sort of stew, bright neon green in color, with plenty of big fat shrimp, and so spicy it can only be eaten using lots of corn tortillas and rice. It is not explosively spicy, but a sneak up on ya, masochistic kind of spicy that keeps you stuffing your face altho you can no longer feel your tongue. And it is SO TASTY that you cannot stop eating until you are stuffed and bursting your britches.
Luckily, shrimp culichi is good cold as well, so you can put it in your fridge and eat it late at night when you have recovered from that initial overstuffing.
We love Mariscos Chihuahua.