Updated April 5, 2026 — Prices updated regularly from EIA data
Route • 1 states
About Interstate 99
Running 51 miles through central Pennsylvania from Bald Eagle Valley to Altoona, I-99 is entirely within one of the highest-fuel-tax states in America. Pennsylvania's 59-cent tax makes filling up along this route notably expensive.
For a trip along Interstate 99, a vehicle averaging 25 MPG would use approximately 1 gallon per 25 miles. At current average prices along the route, budget approximately {perMileCost} cents per mile for fuel. Plan fill-ups in lower-price states whenever possible.
Yes — consistently. Highway-exit gas stations charge 10-25 cents more per gallon than stations just 1-2 miles off the interstate. Whenever possible, exit the highway and drive to a commercial area for competitively priced fuel.
Gas prices along Interstate 99 vary significantly by state due to different fuel tax rates. States like Texas (20 cents/gallon), Missouri (17 cents), and Oklahoma (20 cents) consistently offer the most affordable fuel. Pennsylvania (59 cents) and California (67 cents) are among the most expensive.
Fill your tank before entering high-price states along your Interstate 99 route. Use the GasBuddy app to see upcoming prices and plan fill-up stops at the cheapest available locations. Always fill up when you have a quarter tank remaining — running low limits your options.
Interstate 99 passes through several states on its route. Oil-producing states like Texas, Oklahoma, Louisiana, North Dakota, and Wyoming typically offer the cheapest gas along any interstate that traverses them.