Plot hole: The boys who chase Sarah pick up large stones from a carefully tended lawn, and they find them between the leaves without a bit of searching around. (01:15:45)
Revealing mistake: When Sarah is hit on the head by a stone she's not bleeding, and the injury looks rather dried-up. (01:16:25)
Continuity mistake: When Cathleen is at Dennis' front door, he opens the door and it has three different sized windows that are even on the hinged side of the door. When he closes the door it has three equally sized windows that are now uneven on the hinged side. Right after he closed the door the original three differently sized windows, even on the hinged side, have returned. (01:30:00 - 01:30:25)
Factual error: Cathy and Frank briefly discuss the fact that he can't remember her 'carpool days.' The term carpool originated in the early 1970's. (01:32:00)
Factual error: In one of the final scenes where Julianne Moore is farewelling the gardener at the train station, the platform is shown with yellow caution lines a few feet from the edge of the platform. These where not a safety feature that was present in 1957. (01:36:40)
Continuity mistake: When the train with Raymond leaves the station there's a strange change of light: First the platform lights are on although it's only 4.30 p.m. and it looks quite bright when Cathy arrives at the station. They illuminate the platform brightly throughout almost the whole scene, but in the last shot on Cathy the lights are dimmed and the platform is totally dark. (01:37:05)
Factual error: In the final scene, sidewalk cuts (where a portion of the curb is lowered to permit wheelchair access) are visible, but those were not used in 1957. (01:38:05)
Factual error: At the end of the movie, you see a shot of what is supposed to be the Hartford, CT train station. This station appears to be on the water. Even in the 1950's or 60's, the Hartford train station was not on the water. (01:38:05)
Continuity mistake: Before Cathy goes to the office to take Frank his dinner, she suggests Sybil wrap up his meal. However, she hands her own plate to Sybil (she was sitting at that place eating only minutes before). Frank's meal is still sitting on the table in his place when Cathy takes the Tupperware and leaves.
Continuity mistake: The movie starts in the fall, in Connecticut (New England), so the bright red leaves on the trees are just fine, although the bright green grass is a little less likely. By Christmas there are a few fallen brown leaves, but most of the leaves are still on the trees and still bright red. The grass is still bright green, too, which, considering it would by rights at least have gone dormant and at most been covered by snow, is a bit odd. In early January, when the young boys are coming home from football practice (normally that would have wrapped up in November, but I suppose the warm weather extended the season), they are coming home in sunshine, when it suddenly starts to snow - on the bright green grass and bright red leaves. And at the end, when it's supposed to be March or so, apparently there are roses in bloom (there's a freshly cut one on Cathy's desk) and the apple trees are in blossom, which normally happens in late April or so. I guess Hartford in 1957-58 was the first place to exhibit signs of global warming.
Continuity mistake: When Cathy and her friends are having daiquiris, Cathy brings the pitcher around and says "would anyone like another daiquiri?" and the first woman refuses - and so does Nancy. As Cathy pours one for El, the first woman raises her glass to her lips. The camera shot changes to El and she says "all right." Now the other woman's drink is on the table without enough time for the change. Also, Nancy's glass now has more in it, even though Cathy didn't pour her any.
