Fire officials say the blaze was about 20 per cent contained as today morning.
It threatens about 150 cabins, vacation homes and year-round residences in three communities.
Authorities have told people in those areas to be ready to leave, but had not issued an evacuation order.
The Funny River Fire burning in the 1.9-million-acre Kenai National Wildlife Refuge grew by about 109 square kilometres yesterday.
More than 400 firefighters are assigned to the fire, which is the most active of several large wildfires burning in Alaska.