Owing to the unique history of Whittier, about 85% of the town's 280 year-round residents live in one, 14-story building called Begich Towers, city manager Jim Hunt told CNN.
Originally constructed by the US Army Corps of Engineers in the 1950s, the Begich Towers has 196 units and operates as a condominium complex, according to the building's website.
The six people who came down with the virus all live in that building.
"Upon receiving the positive test results, the patients were immediately placed in isolation -- away from others," Paul Mueller, the CEO of the Eastern Aleutian Tribes, said in a statement.
The organization, formed by six Aleut tribes in 1991, provides healthcare in the region and operates a clinic in Whittier, according to its website.
Isolation in a town that largely lives under one roof can be tough.
"Everyone shares a common ventilation system that is barely working," Hunt said. "That's why its been like a fire -- all hands on deck."
Hunt said that some residents have blocked off the vents in the aging building. The city is also taking more proactive steps, he said.
"We're not in the stage of panic but the tension that has already been at five or six has clicked up," Hunt said.
Hunt said he plans to ask the city council to re-impose some restrictions on public activities as a result.
"We'll probably ratchet back on 100% occupancy of hotels, bars, and restaurants," Hunt said. "I think we'll go to 50% with 10 foot spacing."
Whittier is also uniquely positioned to do Covid-19 testing, thanks to an Abbott rapid testing machine that the town acquired with the help of Sen. Lisa Murkowski, Hunt said.
"We received CARES Act money and now we are providing free testing until the end of September to anyone in Whittier."
In his statement, Mueller encouraged any Whittier resident who has been in close contact with someone outside of their household to get tested at the clinic.
As of Wednesday, Alaska has at least 3,879 confirmed coronavirus cases and 27 deaths, according to Johns Hopkins University data.