There is no maximum age for serving jury duty according to the Administrative Office of the U.S. Courts. However, many courts allow individuals over a certain age to submit written requests to be excused from jury duty based on age.
While there is a minimum age of 18 for serving on a jury, there is no maximum age. The only people who are exempt from jury duty are members of the Armed Forces who are on active duty, members of fire and police departments, and "public officers" of the government. However, local district courts may have their own policies and procedures that allow people over age 70 to request to be excused from jury duty, says the Administrative Office of the U.S. Courts.
For example, the U.S. District Court of South Carolina allows people over 70 to be excused, and the U.S. District Court of California allows those over 75 to submit a request to be excused based on age, as stated on their respective websites.