Two U.S. Forest Service employees were freed Friday after a man and his son bound the workers and held them at gunpoint for about 15 hours in a national forest in rural Northern California, the authorities said.

The two employees, whom the Forest Service chief, Tom Schultz, declined to identify during a news conference on Friday, were not injured, but the ordeal in the Shasta-Trinity National Forest had shaken the workers and their families, he said.

“Both are resting and will need some time to process this experience,” said Brian Tosh, the F.B.I.’s acting special agent in charge in Sacramento.

The two men, identified as Joseph Charles Henrichsen, 49, and his son, Phoenix Henrichsen, 23, were taken into custody early Friday, said Sheriff Jeremiah LaRue of Siskiyou County. The authorities are still investigating the kidnapping, Mr. Tosh said.

Shasta County Sheriff Michael L. Johnson, whose office sent more than two dozen officers to respond to the hostage situation, said Mr. Henrichsen had for years expressed intense complaints about the federal government.

Mr. Henrichsen and his son targeted the federal workers “specifically because of their affiliation with the government,” Sheriff Johnson said.

The men face federal charges of kidnapping government employees, according to the U.S. attorney’s office for the Eastern District of California. If they are convicted, they face sentences of life in prison and a $250,000 fine, the district said.

It was not immediately clear if the two men had legal representation.

Just before 11 a.m. Pacific time on Thursday, a Forest Service law enforcement officer called the Siskiyou County Sheriff’s Office and reported that a man had zip-tied two Forest Service employees and was holding them at gunpoint inside a trailer at a campground near Gumboot Lake, Sheriff LaRue said. The law enforcement officer who called the sheriff said one of the men, the elder Mr. Henrichsen, wanted to talk to the F.B.I., Sheriff LaRue said.

The trailer was in a heavily forested area, accessible only by a one-lane road in mountainous terrain about 6,000 feet above sea level.

Sheriff LaRue said deputies using drones found the trailer around 1 p.m. Footage captured by the drones showed Mr. Henrichsen carrying an assault weapon and walking in and out of the trailer, Sheriff Johnson said. Campers and recreationists in the area were evacuated as hundreds of law enforcement officers surrounded the trailer, he added.

The authorities began negotiating with Mr. Henrichsen around 4:20 p.m. Thursday. He used a victim’s phone to make a call, saying he had taken two hostages “from the Forest Service,” according to a news release from federal prosecutors. It was unclear whom he was speaking to on the phone call.

Mr. Henrichsen also said he had “live rounds ready” to use against anyone who interfered, according to the release.

As law enforcement officers closed in, he mostly remained nonresponsive and covered the trailer’s windows, Sheriff Johnson said.

“I was very apprehensive as to what the possible outcomes were going to be,” Sheriff Johnson said.

Mr. Henrichsen eventually released the two Forest Service employees at about 1:50 a.m. Friday, Sheriff LaRue said. Mr. Henrichsen and his son surrendered less than an hour later, the sheriff said, adding that Mr. Henrichsen said he had an AR-15 rifle, knives and grenades.

The episode was like “something out of a movie,” Sheriff Johnson said. The two employees had been performing “seasonal work” as part of their typical duties before they were taken, Mr. Schultz added.

Sheriff Johnson said the response had included a SWAT team, snipers, hostage negotiators, bomb experts and more. Mr. Schultz, the Forest Service chief, said he had alerted Agriculture Secretary Brooke Rollins, whose department oversees the Forest Service; Kash Patel, the F.B.I. director; and White House officials.