Texas highway map
Sheet TX-10 · 8 route classes · ~80,000 centerline miles state-maintained · highest posted limit 85 mph
A Texas road sign tells you more than the number. The shape of the shield says who built the road and what it is for, and each class of route is numbered by a different rule — some geographic, some purely sequential. Once you can read the shields, a Texas highway map stops being a tangle of numbers.
Zoom in on any metro area to see the loop-and-spur pattern: an inner loop, an outer loop, and radial state highways connecting them. Zoom into open country to see the FM grid, which is denser than the highway network in most of East and Central Texas.
The classes of Texas highway
| Class | Shield | How the numbers work | Examples |
|---|---|---|---|
| Interstate | Red and blue shield | Even numbers run east–west, odd numbers north–south. Numbers increase west to east and south to north. Three-digit routes branch off a parent: an even first digit means a loop or belt, an odd first digit means a spur. | I-10, I-35, the I-410 ring at San Antonio, I-610 in Houston, I-635 and I-820 in the Metroplex |
| U.S. highway | White shield | Same parity rule as interstates, but the numbering runs the other way: low numbers are in the north and east, high numbers in the south and west. | US-59, US-77, US-83, US-90, US-287 |
| State Highway (SH) | Outline of Texas | No geographic rule at all. Numbers were issued in rough order of designation, so a low number simply means an old route. | SH-6, SH-16, SH-21, SH-71, SH-105 |
| Loop | Texas outline with a Loop banner | Leaves a parent route and rejoins it. Numbered in one statewide sequence, not per city — which is why Loop 1 is in Austin and Loop 1604 is in San Antonio. | Loop 1, Loop 12, Loop 289, Loop 375, Loop 410 |
| Spur | Texas outline with a Spur banner | Same sequence as loops, but a spur connects to its parent at one end only and dead-ends at the other. | Spur 366 in Dallas, Spur 5 in College Station |
| Farm to Market (FM) / Ranch to Market (RM) | Square white sign with a Texas outline | One shared numbering sequence. RM is used mainly in the western half of the state, FM elsewhere; the two are legally identical. | FM 1960 in Houston, RM 337 near Leakey, RM 620 near Austin |
| Business route | Parent shield with a Business banner | The old alignment through the middle of a town, kept in service after a bypass opened. | Business I-35 through Waco, Business US-287 through Vernon |
| Park Road (PR) and Recreational Road | Brown or white park sign | Short numbered roads inside state parks and recreation areas, maintained by TxDOT rather than the park. | Park Road 5 into Palo Duro Canyon, Park Road 1 at Bastrop |
Why Loop 1 is in Austin and Loop 1604 is in San Antonio
Loop and spur numbers come from a single statewide list issued in order of designation, so the number carries no information about location — only about age. Loop 1 is MoPac in Austin, which is not a loop in any ordinary sense: it runs north–south and never closes. Loop 12 rings the older core of Dallas, Loop 289 rings Lubbock, Loop 335 rings Amarillo, and Loop 1604 is the outer ring of San Antonio, designated much later than the inner one. Loop 375 in El Paso is the most varied of them: the same number covers Transmountain Road over the Franklin Mountains and the Border Highway along the Rio Grande.
The same logic applies to state highways. SH-6 and SH-16 are two of the longest routes in the system — SH-16 runs from Zapata on the Rio Grande north through San Antonio, Bandera, Kerrville and Llano toward Graham — but their low numbers reflect the 1917 designations, not their length or importance.
Farm to Market and Ranch to Market roads
The FM system is what makes the Texas map look different from other states. It was built from the late 1940s onward to pave the roads between farms and the nearest market town, and it grew into the largest rural road network run by any state. TxDOT maintains roughly 80,000 centerline miles of highway in total, more than any other state transportation department, and FM and RM roads make up the largest share of it.
Two conventions are worth knowing. First, FM and RM numbers come from one list, so there is no FM 337 and RM 337 — only RM 337. Second, an FM road can be a two-lane country lane in one county and a six-lane urban arterial in another: FM 1960 in north Harris County carries more traffic than many state highways. When a city grows around an FM road, TxDOT sometimes transfers it to the city, which is why numbers occasionally disappear from newer maps.
Toll roads
| Toll road | Where | What it does |
|---|---|---|
| SH-130 | Georgetown to Seguin, east of Austin | Bypass of I-35 through Central Texas; the southern section carries the 85 mph limit |
| Sam Houston Tollway (Beltway 8) | Ring around Houston | The tolled main lanes inside the free Beltway 8 frontage roads |
| SH-99 Grand Parkway | Outer ring of the Houston area | The outermost of Houston's three rings, built in segments; when finished it will be the longest ring road in the country |
| Dallas North Tollway | Dallas north through Plano and Frisco | The main north–south alternative to US-75 |
| President George Bush Turnpike (SH-190) | Northern and eastern Dallas County | Outer arc linking Irving, Plano, Garland and Rowlett |
| Chisholm Trail Parkway | Fort Worth south toward Cleburne | Relief route parallel to I-35W |
| Loop 49 | Around Tyler | The only tolled ring road in East Texas |
| SH-255 (Camino Colombia) | North of Laredo | Truck route to the Colombia–Solidarity Bridge, bypassing the city |
TxTag, TollTag and EZ TAG are accepted on each other's roads statewide, so one sticker works everywhere. Several tolled corridors, including Beltway 8 and much of SH-130, run beside free frontage roads carrying the same number.
Speed limits
The general statutory maximum in Texas is 75 mph, and TxDOT may post 80 or 85 mph on a specific stretch when an engineering and traffic study supports it. In practice, 80 mph appears on long rural runs of I-10 and I-20 in West Texas, and 85 mph is posted on the SH-130 toll road between Mustang Ridge, southeast of Austin, and Seguin — the highest posted limit anywhere in the United States. Urban freeway limits drop to 60 or 65 mph inside the big metros, and school zones and construction zones override everything.
Rural two-lane U.S. and state highways are usually posted at 75 mph in daylight conditions, which is why a US-route crossing of West Texas can be nearly as fast as the interstate. FM and RM roads are typically posted lower, often 60 to 70 mph, and frequently pass through unincorporated communities with a sharp drop in the limit and no warning beyond the sign.
Highways worth driving for their own sake
| Route | Where | Why |
|---|---|---|
| FM 170 | Presidio to Study Butte, along the Rio Grande | The River Road through Big Bend Ranch State Park, with grades steep enough to need a runaway ramp |
| RM 335, RM 336, RM 337 | Between Leakey, Camp Wood and Vanderpool in the Hill Country | A tight loop of canyon switchbacks known to motorcyclists as the Three Sisters |
| Ranch Road 1 | Gillespie and Blanco counties | Runs past the LBJ Ranch on the Pedernales River |
| Park Road 5 | Southeast of Canyon | Drops 800 feet from the rim into Palo Duro Canyon |
| Loop 375 (Transmountain) | El Paso | Crosses a pass in the Franklin Mountains between the two halves of the city |
| SH-16 | Zapata to Graham | One of the longest state highways, crossing four regions on the way |