FORESTHILL, California — Firefighters made progress against a huge Northern California wildfire that was still growing and threatening thousands of mountain homes on Sunday, while crews also battled major blazes that blanketed large swaths of Oregon and Washington in smoke. The Mosquito Fire in foothills east of Sacramento spread to nearly 65 square miles, with 10% containment, according to Cal Fire. “Cooler temperatures and higher humidity assisted with moderating some fire activity,” but higher winds allowed the flames to push to the north and northeast. More than 5,800 structures in Placer and El Dorado counties were under threat and some 11,000 residents of communities including Foresthill and Georgetown were under evacuation orders. In Southern California, cooler temperatures and rain brought respite to firefighters battling the massive Fairview Fire about 75 miles southeast of Los Angeles after sweltering heat last week.