Eddie C. Brown, the founder and chief executive of Brown Capital Management, has watched the neighborhood evolve.

Mr. Brown arrived in Baltimore 1973 to work for T. Rowe Price. Ten years later, he founded his investment management firm and moved it to refurbished office space in Mount Vernon. His firm has since expanded to several adjacent buildings.

When a city-owned former mansion in Mount Vernon caught his eye, Mr. Brown decided to expand his portfolio. “The quality and history of these buildings is just incredible,” he said.

Three years ago, he opened the Ivy Hotel, where rooms can cost $600 a night, with a spa and the upscale Magdalena restaurant.

Another entrepreneur, Dennis Richter, immigrated to Mount Vernon with his mother from Germany in 1987 when he was 14. After spending the past decade buying small properties and turning them into apartments and a coworking space, he is planning a $40 million mixed-use development. His project would add about 120 apartments and about 15,000 square feet of commercial space in the heart of Mount Vernon.