Part of the charm of the business district is that 74 of the buildings on the strip are historic, many have remained unchanged for the past two or three generations and the distinct style generates business.
Fourth Avenue is the largest collection of locally-owned businesses in the city, making it a haven for unique products that are attractive to tourists.
In other words, there's nothing else like it.
But a thundering herd of developers have discovered the area can be lucrative and not just for the retail experience. Two new housing developments have been approved and another is waiting in the wings.
Unlike the one and two-story structures that now dominate the landscape, this housing will stretch up - seven, ten, possibly even as high as 14 stories.
Fourth Avenue property has become popular and pricey because it's next to downtown, which has seen $2 billion in development, and the ever popular University of Arizona.
"It's at a turning point, said Mike Peel, Local First Director. "What we do now will set a precedent."
That's why he made a presentation to the Tucson City Council, asking for help.
It's an urgent concern.
While acknowledging that the city's role is limited, he's looking for support for Community Benefits Agreements.
Community Benefits Agreements means the developer and the community sign an agreement where the developer will agree to certain conditions in exchange for community support.
However, those agreements are completely voluntary even though they may be legally enforceable. It depends on whether the developer sees a benefit and the property owner feels its in their best interest.
For the city, besides some zoning rules, CBAs are likely its best tool to make sure Fourth Avenue retains its quaint look and feel.
When voters passed Proposition 207 in 2006, it hamstrung all cities and towns in Arizona from imposing strict rules on property owners.
If the city does something like that, it must compensate the property owner for damages.
"Whether it be this development or future developments, we need to start with this one here," Peel said. "It's a turning point to set the stage for the future."
For Fourth Avenue merchants, it is a future that remains uncertain.