Inspect your home’s foundation for cracks and gaps big enough for a mouse to get through. If you can, climb under your porch or deck, look behind bushes, and inspect hidden places around the exterior of your home. Check holes where any pipes or wires entire your home to be sure they’re sealed properly.
You should also check for gaps in the edges of your doors and windows, and replace or add gaskets where necessary to close them. Additionally, you can look for signs of mice, such as mouse droppings and shredded paper, in the interior of your home to help guide you to any entry points.