About 11% of Altadena is conserved land, roughly 612 acres. There are about 14 miles of mapped trails, and the biggest networks are in San Gabriel Mountains National Monument (4.3 mi), Rubio Canyon (1.7 mi), and The Cobb Estate (1.2 mi).
Conserved land, trails, parks and bike routes in Altadena, measured from OpenStreetMap and USGS data.
Conserved land is a share of the whole town area. Bike lanes are often missing from the map in smaller towns, so that number is likely low.
Conserved doesn't always mean open to visitors. Public access isn't recorded for 1 of 19 parcels. The places listed above are parks and preserves people visit.
Counts include school and college facilities, which aren't always open to the public.
| Town | Conserved | Trails | Parks & preserves |
|---|---|---|---|
| Altadena | 11.3% | 14.4 mi | 14 |
| Pasadena | 13.5% | 39.8 mi | 31 |
Sources: trails, parks, preserves, courts and bike lanes © OpenStreetMap contributors (ODbL), map data as of 2026-09-28. Conserved land: USGS Gap Analysis Project, Protected Areas Database of the United States (PAD-US). Measured against the Census town boundary.
How we measure
"Trails" are OpenStreetMap paths, bridleways, public tracks and unpaved footways, plus footways inside a park or preserve or on a named trail route. Sidewalks are left out. Areas are counted on a 20-meter grid, so overlapping parcels count once. "Conserved" includes conservation easements, which protect land from development but are usually private property. Trailheads are the nearest marked trailhead, public parking lot or information board within about 150 meters of a preserve. Dog rules come from OpenStreetMap when someone has tagged them; otherwise we show what's typical for the land manager, or say the rules aren't recorded.