Loop 1604 forms a complete loop around the city of San Antonio and is the outer of two loops around the city with
Interstate 410 (I-410) as the inner loop. The route has portions that are built to
freeway standards, portions built as a
divided highway, and portions that are just a two-lane rural road. As with I-410, the city's inner loop, the northern half is more urbanized and the southern half, for the most part, remains rural. The loop officially begins and ends at
I-10 east of San Antonio. and Google Earth satellite imagery showed this freeway under construction in 2017-2018. The freeway portion starts as the loop curves towards the northeast at the junction with SH 151. Loop 1604 has diamond interchanges at FM 471 (Culebra Road), Shaenfield Road, New Guilbeau Road, Braun Road, and
SH 16 (Bandera Road). Continuing east from the US 281 interchange, the freeway has interchanges with several local roads to include Gold Canyon Drive, Redland Road, Bulverde Road, and O'Connor Road. The freeway continues east to interchanges with Judson Road and Green Mountain Road before it curves to head to the southeast. Now heading southeast, the freeway has an interchange at
FM 2252 near
Rolling Oaks Mall and an interchange at Lookout Road before it leaves the San Antonio city limits. Upon leaving San Antonio, the freeway enters the
Live Oak city limits before a
cloverleaf interchange at I-35. Southeast of I-35, Loop 1604 enters the
Universal City city limits before reaching an interchange with
SH 218, which provides access to
Randolph Air Force Base. TxDOT has upgraded two intersections between the interchange at SH 218 and Kitty Hawk Road, where Loop 1604 used to have two at-grade turn-offs, one at Palisades Drive and one at Granada Drive. These intersections are now separated from the main lanes and are relegated to the service road at these locations. The same applies to two former at-grade turn-offs southeast of the Kitty Hawk Road interchange at Meadowland Drive and Byrd Boulevard. Meadowland and Byrd now do not intersect the main lanes of Loop 1604 . The last two interchanges of the freeway are located at FM 1976 and
FM 78. Once in the
Converse city limits, Loop 1604 remains a 4-lane divided highway, but has at-grade intersections. The highway passes by the western boundary of
Randolph Air Force Base before curving to the south. The highway re-enters San Antonio city limits prior to its interchange at I-10 at its official beginning and end. ==History==