As of September 2001, there are 5 different Interstate 110s in 5 different states.
- California -- The Harbor Freeway. It extends from San Pedro to Interstate 10 in downtown Los Angeles. It is continued on by SR-110, as it does not meet federal Interstate standards. It was originally signed as US 6 until the California Route Renumbering. It was built between 1962 and 1970.
- Texas -- A "secret" interstate (Signed as US 54), existing only on federal rolls and some maps. However, it was signed as I-110 until the US 54 freeway north of I-10 opened; then I-110 became US 54. It is only 0.94 miles in length.
- Louisiana -- It runs runs north from I-10 in Baton Rouge and was completed around 1984. It is 8.89 miles in length.
- Mississippi -- Runs south from I-10 in Biloxi to US 90. Finished in 1988. It is 4.096 miles in length.
- Florida -- This I-110 shares a secret FL 8A designation. It goes south from I-10 in Pensacola. It is 6.39 miles in length.