In a small town, a true story could be about a family secret. For example, there might be a family that has a special heirloom which is said to have magical powers. But they keep it a secret from the rest of the town because they don't want to be bothered by curious people or have it stolen.
One possible secret in a small town could be a hidden treasure. Maybe a long - ago pirate buried his loot in the outskirts of the town. Years passed and people forgot about it, but some old maps might still hold the key to its location.
Another aspect of secrets in a small town could be related to relationships. There might be a couple who has been secretly in love for years but due to some family feud or social reasons, they have kept their relationship under wraps. They meet in secret places in the town like the old abandoned mill or the back of the churchyard.