Hill Country
Old Tunnel State Park
BirdingHiking
Hill Country
Old Tunnel State Park protects a decommissioned 19th-century railroad tunnel outside Fredericksburg that now shelters one of Texas's most spectacular bat colonies: approximately 3 million Mexican free-tailed bats and 3,000 cave myotis bats emerge at dusk from May through October. Two viewing areas — an upper platform (capacity 100) and a lower platform closer to the tunnel entrance (capacity 70, Thursday through Sunday only) — let visitors watch the evening flight, which can last 20–30 minutes as the bats spiral into the darkening sky. Ranger-led programs on bat ecology run nightly during the season. The lower viewing area consistently sells out two weeks in advance; advance online purchase is mandatory as no tickets are sold on-site. Children under 4 are not permitted in the lower area. A short nature trail of under half a mile is accessible year-round from sunrise to 5 p.m. for visitors who want to see the tunnel and surrounding cedar-juniper habitat outside of bat season. No pets, alcohol, or camping are permitted; bring your own drinking water as none is available on site.
Shade Details
Live oak woodland around the viewing area provides decent shade. Evening visits don't require shade since the bats emerge at dusk.
Conditions & Tips
Bat season runs roughly May–October. Colony peaks August–September. Upper platform reservations recommended. Check TPWD site for current bat count estimates. Bring insect repellent.
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