The Monarch Grove Sanctuary is a grove of tall eucalyptus among a Monterey Pine forest that is used for seasonal roosts of Monarch butterflies (primarily November-February). The tall trees protect roosting Monarchs from wind and the specific sub-climate at the site almost never freezes. Historically, there were thousands at this location, but numbers have dropped in the past decade and can vary year-to-year from almost none to ~10,000. Monarchs are the primary attraction here, but this is a public-access site to Monterey Pine habitat amid a neighborhood of mostly single-family homes. 

The Hot Spot boundaries are (clockwise) Lighthouse Ave., 17-Mile Drive, Short St., and Grove Acre Ave. This includes the Pacifci Grove softball ballpark along Short Street, and adjacent eucalyptus, pine, cypress, and live oak habitat. A beehive near the ballpark was frequented for 8 consecutive winters by a male Summer Tanager.

Birds in the Sanctuary are pine woods residents (Anna's Hummingbird, Steller's Jay, Hairy & Acorn Woodpeckers, Pygmy Nuthatch) or winterers (Ruby-crowned Kinglet, Townsend's Warbler, Golden-crowned Sparrow). 

There is just one walking trail (ADA accessible) through the eucalyptus grove frequented by the Monarch butterflies (Nov-March). It goes downhill from Ridge Road to Grove Acre Avenue. An outhouse at the Grove Acre end provides pit-toilet facilities during the butterfly season.