[PAR35]

Then you believe wrong.

Exits in Texas match the mileposts. The first exit in Texarkana is Exit 222. https://www.google.com/maps/@33.4703604,-94.0448224,3a,75y,233.29h,77.79t/data=!3m6!1e1!3m4!1s0DoNshgoxAUWbPGiqwuUSg!2e0!7i13312!8i6656!6m1!1e1

First Milepost I spotted 223. https://www.google.com/maps/@33.4698619,-94.0538365,3a,75y,268.28h,83.16t/data=!3m6!1e1!3m4!1snhfOrZjHH8GbD8bjV2dXYw!2e0!7i13312!8i6656!6m1!1e1

[okie01]

Kinda comes under the heading of "Who you gonna believe? Me? Or your lyin' eyes?", doesn't it?

However, I know damn good and well that I saw an 838 milepost at that point when I arrived in Texas...in 1967.

And the date could be the key to the conundrum. I-20 wasn't there when I moved to Texas. Or, at least, it had not been extended around the south sides of Dallas and Fort Worth to join with I-30 west of Fort Worth.

I even drove a good friend of mine up from Dallas to Texarkana to show it to him. So, I know it was there...once.

[7MMmag]

I-30 does not cross the entire state (of Texas).

I-20 does not either, stopping (or beginning, depending upon how one looks at it) near Van Horn (or more precisely, Kent, Texas).

I-30 runs only from Texarkana to West of Ft. Worth. From there on (Westbound) the road designation is 1-20...

Distance of Interstate 20 across Texas = 636.1 miles

Distance of Interstate 10 across Texas = ‎878.6 miles.