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San Antonio Area Freeway System
State Loop 1604
(Charles W. Anderson Loop)

This page last updated March 14, 2024

Loop 1604 highlight map
Loop 1604 highlight map

This page covers the freeway segment of Loop 1604 across North and West San Antonio from FM 78 in Converse to US 90 West. The remainder of the 94 mile loop — which is the longest loop in Texas — is non-freeway, most of which is a two-lane rural road.

Length (freeway section): 39 miles


On this page:

Overview Roadway
Lanes Access
Exits Speed
Special features
and notes


When the first segments were built in the 1960s, it would have been hard to fathom that Loop 1604 North would become the busy beltline that it is today. While the southern half remains mostly in its original configuration as a two-lane rural state highway (for now), the northern arc has been expanded to a four-lane freeway, with work now underway to expand it to 10 lanes.

Loop 1604 forms the outer of San Antonio's two beltways. The freeway portion serves Joint Base San Antonio Randolph and Camp Bullis, the Forum and Live Oak Town Center shopping centers, Rolling Oaks Mall, the Stone Oak area, the University of Texas at San Antonio's (UTSA) main campus, Six Flags Fiesta Texas, the Shops at La Cantera and the La Cantera development, The Rim development, the corporate headquarters campuses for Valero Energy and NuStar, the Alamo Ranch area, Sea World and the Westover Hills area, and the suburban cities of Converse, Universal City, Live Oak, Selma, Hollywood Park, Shavano Park, and Helotes.

The corridor runs through increasingly dense suburban residential areas interspersed with moderate to heavy commercial development, especially at the main nodes near I‑35, Bulverde Rd., US 281, Blanco Rd., I‑10, Bandera Rd., Culebra Rd./SH 151, and Potranco Rd. The area outside 1604 from Bandera Rd. to US 90 is expected to add roughly 200,000 people between 2020 and 2030.

A five-level "stack" interchange exists at US 281 with cloverleaf interchanges at I‑10 and I‑35. There is a single flyover connector from southbound Loop 1604 to eastbound SH 151 as well as from southbound Loop 1604 to US 90 eastbound. Work to replace the cloverleaf at I‑10 is underway, as is a project to add a new direct connector from SH 151 to northbound Loop 1604.


Loop 1604 is sometimes mistakenly referred to as FM 1604. However, FM 1604 is in North Texas. (See the History section below for more info.)

Roadway details

  • 4 lanes along entire route
Loop 1604 access roads map
  • Continuous access roads along entire route except at the following locations:
    • At the railroad tracks between FM 78 and FM 1976
    • At I‑35
    • At the railroad tracks between Nacogdoches Rd. and Green Mountain Rd.
    • Northbound through the SH 151 interchange (project currently underway will add this)

Click here for a list of Loop 1604 exits.
Loop 1604 speed limit map
  • 65 mph between FM 78 and Nacogdoches Rd.
  • 70 mph between Nacogdoches Rd. and US 90
Loop 1604 special features map
  • TransGuide coverage along entire route:
    • Full coverage from FM 78 to I‑35 North
    • Auxiliary coverage between I‑35 North and I‑10 West
    • Full coverage from I‑10 West to US 90 West
  • Partial directional interchanges at the following locations:
    • SH 151 — access roads provide connectivity from SH 151 to Loop 1604 northbound and from northbound Loop 1604 to SH 151, while a signalized left turn and ramp provides access from SH 151 to southbound Loop 1604
    • US‑90 — full connectivity is provided by access roads
  • VIA Metropolitan Transit University Park & Ride located under I‑10 interchange
  • Carpool parking ("Park & Pool") lot on northbound-side ramp to/from FM 78
  • Unusual yield sign arrangement at Loop 1604 interchange (click here for more information)
Loop 1604 traffic map

Generally, volume is moderate to heavy along entire route. Loop 1604 experienced ridiculously blistering traffic growth during the 1990s and early 2000s, with average 10-year traffic counts up well over 300% along nearly the entire route, and up nearly 1000% near Bandera Rd. for a time. However, that has moderated substantially during the past decade (mainly due to capacity constraints), although most of the western arc has continued to see substantial growth during that time. After current expansion projects are complete, traffic counts will almost certainly surge along the northern arc once again.

Recurring congestion occurs during morning peak periods northbound/eastbound between Culebra Rd. and I‑10 West, southbound from Shaenfield Rd. to SH 151, and most of westbound Loop 1604 across the North Side. In the evenings, recurring peak period congestion occurs westbound from US 281 North to Bandera Rd., southbound from Shaenfield Rd. to SH 151, eastbound from the UTSA area to Bitters Rd., and eastbound from US 281 North to I‑35 North.

Traffic volume legend
LOCATION 2002 2012 2017 2019 2021 2022 '12-'22
E of FM 78 23,000 31,000 41,129 41,903 40,724 43,030 +38.81%
W of FM 78 43,000 55,000 67,174 67,555 61,928 61,606 +12.01%
S of Pat Booker Rd. 59,000 64,000 67,020 62,190 79,271 78,128 +22.08%
N of Pat Booker Rd. 59,000 72,000 98,853 102,231 84,141 82,167 +14.12%
W of I‑35N 67,000 91,000 123,230 126,780 111,655 110,652 +21.60%
N of Lookout Rd. 67,000 91,000 116,417 123,206 103,520 101,808 +11.88%
N of Nacogdoches Rd. 58,000 88,000 111,072 113,497 92,035 91,556 +4.04%
W of O'Connor Rd. 69,000 88,000 112,228 118,185 111,204 109,716 +24.68%
E of Gold Canyon Rd. 86,000 105,000 121,579 126,300 126,961 115,802 +10.29%
W of US 281N 104,000 120,000 125,989 131,146 100,343 125,841 +4.87%
E of Bitters Rd. 85,000 113,000 161,000 164,218 154,706 116,008 +2.66%
W of NW Military Hwy.         127,585 125,360 N/A
W of Vance Jackson Rd. 85,000 128,000 142,249 146,905 126,819 119,379 -6.74%
W of I‑10W 71,000 113,000 131,409 134,730 116,488 112,733 -0.24%
N of Hausmann Rd. 61,000 100,000 114,499 116,399 101,084 104,741 +4.74%
N of Bandera Rd. 59,000 100,000 122,687 136,161 108,092 110,080 +10.08%
S of Bandera Rd. 41,000 83,000 89,976 102,305 115,987 120,361 +45.01%
S of Braun Rd.         108,514 112,745 N/A
N of Culebra Rd. 24,000 74,000 97,685 119,406 128,082 130,444 +76.28%
S of Culebra Rd. 29,000 85,000 86,833 115,180 131,343 129,333 +52.16%
S of SH 151         75,535 72,309 N/A
N of Potranco Rd. 19,300 34,000 33,664 31,528 45,023 42,774 +25.81%
S of Potranco Rd.         67,160 63,280 N/A
N of US 90W 16,300 26,000 27,402 41,185 45,285 45,557 +75.22%

(NOTE: In 2021, TxDOT changed the location of several traffic counting stations. New stations will show no history prior to 2021.)


Media gallery

Click here for historical photos of this freeway.

Click here for video of this freeway.

Construction projects

Click here to view information for all projects in this corridor.

Future plans

In 2018, plans were announced to upgrade the section from I‑10 East to FM 78 to a full freeway, which is now estimated to start after 2030. Details of those plans are here.

Plans had been in the works since around 2005 to expand Loop 1604 from I‑35 North to Bandera Rd. by adding tolled managed lanes in the median between the existing lanes. The environmental study for that project, however, was delayed several times over the years due to changes in its scope caused by the unexpected availability of funding for non-tolled expansions in the western corridor and, later, due to funding shortages for the study itself.

A study is currently underway on possible future improvements and expansions of the western segment from Bandera Rd. south to US 90.

TxDOT plans to eventually expand all of Loop 1604 south of US 90 to a four-lane divided highway. The first two projects are now complete. Two more projects are expected to start in the next decade. Click here for more information on these projects.


Loop 1604 was authorized by Transportation Commission Minute Order 72928 (June 30, 1977). It's named "Anderson Loop" for former Bexar County Judge Charles W. Anderson who advocated for an outer loop during the mid 1950s. Anderson served as Bexar County Judge from 1939 until his death in 1964.

The first plans for an outer loop around San Antonio emerged in 1956, and ground was broken on the first segment — from US 281 to I‑10 on the North Side — on August 4th, 1960. Most of the northern half was built as new "greenfield" route, while most of the southern half usurped the existing routes of FM 2173 and FM 1518. As those southern sections were incorporated into the loop, improvements were made such as straightening some of the more crooked sections and building bypasses at Somerset, Elmendorf, and Lone Oak. The initial plan for the loop was to build a "starter" two-lane road, then come back later and expand to a four-lane divided highway, and the state acquired plenty of right-of-way for future expansions.

Loop 1604 was originally planned to be numbered Loop 26. In 1958, the western arc of today's Loop 1604, from I‑10 south to Macdona, was reportedly planned to be numbered Loop 334. However, for unknown reasons, the first sections of the loop to be built were instead numbered FM 1604.

When the loop was nearing completion in 1977, state officials were ready to change the designation from FM to Loop. Because loops are typically assigned a one to three digit number, this should have resulted in a new number being assigned. But the route number 1604 had already become so ingrained with area residents that state officials decided to simply switch the route prefix from FM to Loop, keeping the route number as 1604. As a result, until 2020, Loop 1604 was the only four-digit loop and one of just four four-digit state highways in Texas that is not a Farm-to-Market road. (In 2020, Loop 1853 was approved for a bypass around Madisonville. Although it is a new-location route, the route number was requested by Madison County to commemorate the year the county was established.) The FM 1604 designation has since been recycled and is in use on a short route in Irene, Texas, east of Hillsboro. Regardless, many locals still continue to (incorrectly) refer to Loop 1604 as FM 1604.

In the late '70s and most of the '80s, the northern and western sections of Loop 1604, which were still mostly two-lane farm road, became known as "The Death Loop" due to a high number of fatal accidents caused by the high volume of traffic — especially truck traffic, intersections, limited sightlines due to the hilly terrain, and dark stretches at night.

Loop 1604 history map

The opening dates below up to 1981 are for the original two-lane rural road.

Loop 1604 north of Culebra Rd. looking south in 1988

Loop 1604 north of Culebra Rd. looking south in 1988
(Photo courtesy of TxDOT)

Loop 1604 at Green Mountain Rd. looking southeast in 1991

Loop 1604 at Green Mountain Rd. looking southeast in 1991
(Photo courtesy of TxDOT)

Sign along Loop 1604 in 1983

Sign along Loop 1604 in 1983
Several of these signs were placed along Loop 1604 as an attempt to reduce fatalities along the "Death Loop" and to let the public know that the Highway Department was working on a fix.
(Photo source: Helotes Echo, October 14th, 1983)

More historical photos of Loop 1604 are available here.