The Preserve Down Marsh Creek Road You Can Only Enter by Bus

Registration for this fall's Vasco Caves tours opened at 9 a.m. on Tuesday, October 6, 2026. When we checked that same day, both tours on the East Bay Regional Park District calendar showed "Full," and waitlists were open. The tours run on two Saturdays, November 7 and November 14. They meet at the Round Valley Regional Preserve staging area at 19450 Marsh Creek Road, a short drive from Vineyards at Marsh Creek.

This is the only way to see Vasco Caves Regional Preserve. You cannot drive in, park, or walk in on your own. The rules that keep it this way also explain a lot about Round Valley, the open preserve whose parking lot the tour buses leave from.

Both November Tours Showed Full on Opening Day

Here are the details of the two posted tours, from the District's registration pages:

1. Saturday, November 7, 2026, 9:00 a.m. to 1:00 p.m. Registration runs through November 4 at 11:59 p.m.
2. Saturday, November 14, 2026, 9:00 a.m. to 1:00 p.m. Registration runs through November 10, and two people were already on the waitlist when we checked.

Both tours cover 2 to 3 miles, are open to ages 10 and up, and celebrate National Native American Heritage Month. The listing calls the preserve sacred to local California Indian communities and a refuge for golden eagles, fairy shrimp, and tiger salamanders.

When we searched the registration site for "Vasco," these were the only two future tours. Nothing was listed for later in 2026 or for spring 2027, and no tours were posted from the District's other staging point, Brushy Peak Regional Preserve in Livermore. The District says it offers Vasco tours "on select dates in fall, winter, and spring," so more dates may be posted later. For now, the fall calendar is two buses and two waitlists.

Why the Gate Stays Locked

The East Bay Regional Park District and the Contra Costa Water District bought the Vasco Caves land together, and the Park District runs it under an agreement with the water district. The park page states the rule plainly:

"All access is by advance reservation guided tours only. The Preserve is not open to general public access in order to protect the Reserve's unique resources."

The District gives three reasons the preserve is protected: rare plants and animals listed by the state and federal governments, rock outcrops that are easily damaged, and Native American archaeological sites. The rock art in those sites belongs to a cultural complex that goes back nearly 10,000 years. The page also says the land's resources survive today "because of the land's isolation and past efforts to keep it secret." Sandstone outcrops rise sharply out of the rolling foothills east of Mount Diablo. The grasslands show how well native bunchgrass can be restored with sheep grazing. The wildlife list includes endangered red-legged frogs, tiger salamanders, fairy shrimp, kit foxes, eagles, and other nesting raptors.

An earlier article in The Press described what visitors see on the bedrock: painted rock art, small carved hollows called cupules, and grinding holes called mortars. It said the area is sacred to Bay Miwok, Ohlone, and Yokuts communities and is still used for ceremonial gatherings. The same article noted that vernal pools form in the rainy season and hold fairy shrimp, including the endangered longhorned fairy shrimp. That article also described the tour as a longer loop than the 2 to 3 miles listed this year, so go by the current listing for distance.

The protections apply during the tour too. Groups are limited to 22 people. Everyone stays with the leader and on approved routes. Collecting anything, taking photos, and using a cell phone or GPS are all prohibited. No photos are allowed, so the only way to know what the place looks like is to go.

The Bus Leaves From a Parking Lot You Already Know

The Vasco tour starts at the Round Valley staging lot. From there, a District bus takes the group into the preserve. The District's intro letter for Round Valley departures asks you to arrive 15 minutes early. It says to plan on a 20-minute shuttle ride and to be back around 1 p.m. The letter also lists what to bring:

• Layered clothing and supportive hiking shoes
• Gaiters, a hat, sunscreen, and sunglasses
• Food and drink you can carry
• Binoculars

To reach the staging area from Brentwood, take Walnut Boulevard south to Marsh Creek Road and turn right. Where Marsh Creek Road meets Camino Diablo Road, bear right to stay on Marsh Creek Road. The staging area is on the left. Parking is free, and drinking water is available at the staging area.

Round Valley was also kept from development on purpose. Thomas Murphy, an Irish immigrant, bought the land in 1873 and started a ranch. His grandson, Jim Murphy, sold the core 700 acres to the Park District in 1988. He wanted the land kept as open space instead of being built on or used for a garbage dump, which had once been proposed. The District says the valley was probably once a boundary where groups from the East Bay and the San Joaquin Valley met to trade and socialize.

Round Valley Is Running on Its Own Fall Rules

Round Valley covers 2,191 acres and is open to anyone without a reservation. It still has a few rules and closures this season that are good to know before you go.

The dog rule comes from the same concern for wildlife that keeps Vasco Caves closed. Round Valley is home to the endangered San Joaquin kit fox and is near the northern edge of its range in California. The District notes that dogs can spread disease to kit foxes and keeps dogs out because the habitat is sensitive. Golden eagles nest in the preserve, and burrowing owls live in old ground squirrel burrows.

Fall is also when the valley starts to change. The California red-legged frogs, western toads, western pond turtles, and Pacific tree frogs in Round Valley's ponds and streams breed when the winter rains begin. The Miwok Trail follows Round Valley Creek starting about half a mile from the staging area. The creek runs until late spring or early summer and then dries into separate pools.

The Free Hike From the Same Lot

On Saturday, November 28, 2026, the District is leading "Fall in the Valley," a naturalist-led hike from the same staging area. It goes out to the Round Valley campground and back to explore how the valley shifts from fall to winter.

The listing describes the route as uneven and unpaved, with "only a couple hundred feet gain in elevation." It says the hike is best for teens and adults, and heavy rain or a lot of mud will cancel it. The campground at the far end is the Backpack Camp, a 3.6-mile hike in from the Marsh Creek Staging Area. The water supply there isn't working right now, so carry all the water you'll need for the round trip. By November 28, the preserve closes at 5 p.m., but a hike that ends at 12:30 leaves plenty of daylight.

If You're on the Waitlist

Waitlist signups for both Vasco dates were open when we checked, and registration for each tour runs until November 4 and November 10. You can sign up through the District's registration page by searching "Vasco," or call 1-888-327-2757, press option 2, and then option 3. The District's registration page hides the tour fee behind a "View fee details" button, and we couldn't see a dollar amount when we checked. Older news articles give prices from years ago, so call the District for the current fee.

There is one more event that month with a similar theme. On Sunday, November 1, 2026, at 9 a.m., Brushy Peak Regional Preserve in Livermore is hosting a Native American Heritage Month hike. It is a separate Brushy Peak outing and does not go into Vasco Caves. Because the District offers Vasco tours in winter and spring as well as fall, it's worth checking the registration site again over the next few months for new dates.

For more ways to spend the season nearby, our guide to the farms around Vineyards at Marsh Creek this fall covers the harvest calendar along the same roads.

Getting a spot on these tours means watching for the opening date and signing up right away. Planning a move into or out of a 55+ community works much the same way. Timing, paperwork, and the right people all have to line up. At Jo Ann Luisi, we help Tri-Valley homeowners and their families plan those transitions step by step, with time to spare. If a move to Vineyards at Marsh Creek is on your calendar, request your free home valuation and consultation, and we'll start with a timeline that fits your family.