Kylie Late then made the second of two foul shots with 10 seconds remaining to extend the Cougars' lead to 52-50.
Smithsburg's Emily Hargreaves missed a 3-pointer with six seconds to go. Elisa Owens grabbed the offensive rebound, but she missed her shot with three seconds left.
Metheny grabbed the defensive rebound for Catoctin with one second remaining and held the ball as time expired.
"We knew that they like to pound it inside," Catoctin coach Amy Murray said. "We wanted to pack it in on the inside with a 2-3 zone defense. We wanted to force them to shoot from the outside. We boxed them out to get the defensive rebounds."
Late finished with 17 points and three assists, while Metheny added 16 points and nine rebounds for Catoctin. Katelyn Keilholtz had 11 points, including three 3-pointers, seven rebounds, three steals and three assists for the Cougars, while Woelfel had 14 rebounds and three steals.
Sprecher finished with 18 points and eight rebounds, Emily Hargreaves had 10 points and three assists and Allie Nickels added nine points and nine rebounds for Smithsburg. Sara Rishell had 13 rebounds, nine blocked shots and three assists for the Leopards, while Taylor Belella added six rebounds.
"We had a very good season," said point guard Marissa Luipersbeck, Smithsburg's only senior starter. "We impressed a lot of people who didn't expect us to do as well as we did. There is a lot of talent returning next year for our team. They will have some experience and they will lead the team."
Catoctin 52, Smithsburg 50
Late 17, Metheny 16, Dewees 2, Keilholtz 11, Woelfel 6. Totals 21 6-10 52.
Belella 3, Hargreaves 10, Sprecher 18, Luipersbeck 3, Rishell 2, Nickels 9, Owens 5. Totals 20 7-10 50.
Catoctin 10 11 16 7 8 -- 52
Smithsburg 11 13 10 10 6 -- 50
3-point goals -- Catoctin 4 (Late, Keilholtz 3), Smithsburg 3 (Belella, Hargreaves 2).