This park is a small piece of the 2217 acre Rancho Ulistac land grant made by Governor Pio Pico in 1845, supposedly named after an Ohlone chief. It is widely accepted that there was an Ohlone settlement around the river at this spot.
The Ulistac Natural Area is a popular place for bird watching, wildlife observation; and of course, geocaching. The 41 acre (16.6 hectare) park is just east of the west side Guadalupe River Trail and is bordered on the west by Lick Mill Blvd, on the north by Tasman Drive and on the south by housing developments. Formerly part of a golf course, it's being restored as an exhibit site for native plants and animals; assisted by irrigation with recycled water. The future of this park was threatened by the crucial need for football parking, but its existence is secure for now thanks to the Santa Clara County Open Space Authority. This park also has a page on the waymarking site: http://www.waymarking.com/waymarks/WMDVNF_Ulistac_Natural_Area_Santa_Clara_CA
Park hours are from sunrise to one-half hour after sunset. You may enter from Lick Mill Blvd., where there is on-street parking, or from the west-side river trail. The west-side trail is packed gravel not suitable for road bikes, but the east side is paved from Alviso to downtown San Jose. You can cross over the river at Tasman Drive or the bike/pedestrian bridge further south near the River Oaks VTA light rail station. There's also a park-and-ride lot by the station. There are no facilities in the park itself, but restrooms and picnic tables are across the street at Lick Mill Park. Dogs are permitted, but must be leashed. Note that street parking is prohibited during events at the nearby stadium.
The cache is a camo'd plastic jar big enough for small trade goods and a geocoin or two. The present location is in a small live oak adjacent to the trail. Be warned that this park is also an informal doggy walk spot and that you should watch your step. Curious dogs possibly contributed to the demise of previous caches, so this one is hanging above ground about four feet (1.2m) high in leafy cover. Cell phone GPS's seem to have problems here, but it is not a micro and there are not that many spots for it to hide. Initial contents include some small swag and a FTF prize. Mosquitoes can be a nuisance at certain times of the day in spring and summer months.
Congratulations to lel_h and Whirlycrackercat for the FTF!