Towards the end of the movie, Richard tells Maegan that she is going to take a trip down "The Geneseo", The river running through Rochester is " The Genesee " River. Geneseo, is a town about 45 minutes south of Rochester.
It is mentioned that two of the girls killed had recently been to the aquarium. Rochester, NY does not have an aquarium.
As she begins to research the crimes, Megan sets up an office in her attic; there is a scene showing her sticking Post-It notes to a brick wall or chimney. Post-It notes were not commercially available until 1977, and that was in just 4 test markets nationally. They were debuted in US stores as Post-It notes in 1980.
Also, When they visited the Webster Police Chief in his office, they are clearly in a sky scraper. The Webster Police HQ is a two story building next to a park and a library.
After speaking with the Webster Police Department the officers are going to their car in a parking garage. There is no parking garage in the village of Webster.
When Megan goes into Len's house to talk to her, she is not wearing latex gloves, her fingerprints would be all over everything.