San Bernardino rewards visitors who arrive with realistic expectations. This is not a polished resort city where attractions line one walkable boulevard. Its appeal is a mix of Route 66 history, railroad heritage and quick access to the mountains.
My ten places to start
I would put the Original McDonald’s Site and museum, the San Bernardino History & Railroad Museum at the historic Santa Fe Depot, and a drive along the old Route 66 corridor near the top of the list. The California Theatre adds another piece of local history, while the Arrowhead landmark on the mountainside is something you will notice long before you reach it.
For outdoor time, Glen Helen Regional Park is an easy option and the San Bernardino National Forest opens up a completely different landscape above the city. If you have a car, Lake Arrowhead is close enough to turn a city morning into a mountain afternoon.
I would also make time for a proper local meal, especially Mexican food with some history behind it, rather than defaulting to freeway chains.
Don’t try to walk everything
The important practical point is distance. San Bernardino is spread out and a car makes sightseeing much easier. Pick two or three stops that fit together geographically rather than zigzagging across the city.
San Bernardino works best when you treat it as both a destination and a base. Spend time with its Route 66 story, then use its position at the foot of the mountains to explore farther.