Let me narrow that question. Most on my mind these days is the Mission’s eastern boundary. The question arose as I looked at the map for our Mission Wakes Up Series – a collection of essays created by readers and residents who agree to go out, photograph a block and then send in the photos, captions and sometimes a small story for us to post the same day.

Slowly, but surely, more than four dozen residents have offered to do this, and they’re filling in the map day-by-day. At present, we’ve marked the 101 Bayshore Freeway as the eastern border, mostly because it feels like a sharper dividing line than Potrero Avenue. Also, we cross Potrero to cover news, but generally that news happens between Potrero and the freeway. When news happens east of the freeway, we tend to, well, draw the line.

Bulldozers moved in to build the 101 Bayshore in the 1950s, but instead of being at the forefront of a whole new set of freeways, it seemed to lower the curtain on more extensions. Chris Carlsson writes on FoundSF that in 1953, the city opened 101 Bayshore Freeway or “what became known as ‘hospital curve’ both for its location behind General Hospital and its high rate of accidents.”

Plans were afoot for more freeways and the San Francisco Chronicle published a map in 1955 of the city’s various plans, encouraging officials to go forward. Public opposition, Carlsson writes, kicked in. It’s thanks to public outcry that we don’t have, for example, the Mission Freeway, which would have run alongside Mission Street to connect at Duboce.

The 101 Bayshore altered Potrero’s landscape, isolating residents wedged into the two to three blocks between Potrero Avenue and the new freeway. Even today, residents have mixed views on where they fit. At the southern end of the Potrero/101 wedge, there is a stronger identity with the Mission; at the northern end, a distinctly Potrero allegiance runs deep.

Richard Fong, who has lived on San Bruno off 24th Street since 1962, said they’ve always been more Mission, as 24th Street and its restaurants are easier to get to than the commercial district in Potrero.

Patrice Catania on Utah agreed. She rarely goes to Potrero Hill’s commercial strip. Philz Coffee on 24th Street is her go-to place.

San Francisco General Hospital and an undeveloped strip of land just north of it separate Fong and Catania from their neighbors north of 18th Street on Utah and San Bruno.

We’re right on the fence, said Scott Minneman, who has lived on Utah with the artist JD Beltran for 14 years.

Near 16th Street on San Bruno, which abuts the freeway, Jonathan Hernandez, a five-year resident of the neighborhood, said he considers it the Mission “or the border of Potrero… The zip code is the same 94110, so…”

But longer-term residents are were adamant.

“This is Potrero Hill, I was born and raised here and I know the difference between Potrero and the Mission,” said Anthony Blea, who has lived on San Bruno for 53 years.

Leo Costello, who has resided at Utah and 17th for his entire 86 years and accordingly takes a long view, agreed. “This is Potrero Hill, I was born and raised here. I’ve always considered the avenue is the marker, not the freeway because the freeway wasn’t here when I was born.”

On Mariposa and Utah, Michael Jones, who has been here for 14 years, pointed out another indicator: The street names. “Utah, Florida, Mariposa, those are associated with Potrero. The Mission is known by other names, like Valencia.”

Andrea Valencia contributed to the reporting of this story.