

In terms of contributions to the architectural record, this style is Sentry's most prevalent. All of these buildings date to between the mid 1960s and mid 1970s, and feature a full-length concourse with anywhere from 8 to 21 arches overhead. The upper-right store happens to be located on Echo Lane and South Ridge Road in Ashwaubenon, and was actually specifically mentioned on an episode of MST3K where Joel Hodgson reminisced about the sixties. As far as I know, there is only one example of this prototype still in operation as a Sentry today: Cottage Grove Road in Madison. (No picture yet, unfortunately.)
I'm a little unclear about the history of the chain; since the only write-up I've seen is the one on Wikipedia. Assuming that's accurate, the chain got its start in the 1960s, benefited from the subsequent exit of Kroger, A&P, and National from Wisconsin, was more or less acquired by the Fleming Companies sometime along the way, and retrenched and closed a bunch of stores in the early 2000s (selling others to independent operators) after Fleming declared bankruptcy. Is there more to the story than that, though?

