Bold states denote clinched state for that route; bold route number denotes clinched route; non-bold denotes travelled but not clinched.
I don’t count certain routes that were not Interstates when I travelled them (I-14, I-99 in New York, the fake I-87 in North Carolina).
H-1
I-4: FL
I-10: AZ, LA, MS, AL, FL
I-12: LA
I-16: GA
I-17: AZ
I-20: GA, SC
I-24: GA, TN
I-25: NM, CO
I-26: NC, SC
I-30: TX, AR
I-35: TX (incl. I-35E)
I-40: NM, AR, TN, NC
I-44: MO
I-55: AR, MO, IL
I-57: IL
I-59: AL, GA
I-64: MO, IL, IN, KY, WV, VA
I-65: AL, TN, KY
I-66: VA, DC
I-68: WV, MD
I-70: CO, MO, IL, IN, OH, WV, PA, MD
I-71: OH
I-73: NC
I-74: NC
I-75: FL, GA, TN, KY, OH, MI
I-76 east: OH, PA, NJ
I-77: OH, WV, VA, NC, SC
I-78: PA, NJ
I-79: WV, PA
I-80: OH, PA, NJ
I-81: TN, VA, WV, MD, PA, NY
I-83: MD, PA
I-84 western: ID
I-84 eastern: PA, NY, CT, MA
I-85: AL, GA, SC, NC, VA
(Honorable mention: Former I-86: CT)
Current I-86 eastern: NY
I-87: NY
I-88 eastern: NY
I-90: IL, OH, PA, NY, MA
I-91: CT, VT
I-93: MA, NH
I-94: IL
I-95: FL, GA, SC, NC, VA, DC, MD, DE, PA (only missing the new ramps completing I-95), NJ, NY, CT, RI, MA, NH, ME
I-97: MD
I-99: PA (see note above about NY)