"God bless this field, and God bless Nick," Dave Bowers said during the ceremony at Martin L. "Marty" Snook Memorial Park.
Bowers, of Clear Spring, is the brother of Adenhart's mother, Janet Gigeous.
During the ceremony, a sign was unveiled with the words "Halfway Little League Nicholas James Adenhart Memorial Field."
At the bottom of the sign is the Pete Rose quote: "You owe it to yourself to be the best you can possibly be ... in baseball and in life."
Also on the sign is the number 18 and the letter G, which represents the local Gehr team on which Adenhart played. Also on the sign is the number 34 and the letter A, to recognize Adenhart as a member of the Los Angeles Angels.
Adenhart's mother said she is still working through dealing with her son's death. A priority has been doing things in his memory, she said.
"This is top on the list," Gigeous said.
Gigeous and Adenhart's father, Jim Adenhart, and other relatives attended Sunday's ceremonies.
Gigeous paused as she continued to think about her son.
"I don't think I can describe it. I really don't. He's missed so much. Certainly our lives will never be the same," Gigeous said.
For now, she said, the family is living by Adenhart's outlook on life: Never quit.
Besides naming the major league field in Adenhart's memory, the complex of four fields was named in honor of Joseph E. Widmyer, who worked to make baseball a reality at the park. The other fields are a T-ball field, a minor league field and a senior league field.
Widmyer was the first director of parks in Washington County and his work in the 1970s and thereafter to develop parks came when the county began to receive funding to build a parks system, officials at Sunday's ceremony said.
Before Halfway Little League got its home at the park, games were played in a cornfield off Sterling Road, officials said.
"The county jumped on it and went crazy with the parks," Widmyer's son, Joe, said. "It's nice that he continues to be recognized."
Joseph E. Widmyer died in 1981, his son said.
Jim Sterling, director of parks recreation and facilities for Washington County, said Halfway Little League approached him about the dedication proposals.
The plan was presented to the Washington County Recreation and Parks Advisory Board and the Washington County Commissioners before it was finalized, Sterling said.
During the ceremony, Joe Widmyer encouraged children in the audience to always slide at the newly named Nick Adenhart field.
"A little bit of Nick Adenhart might rub off on you," Widmyer said.