When speaking about geographic location, IN is used to indicate big places, for example:
- Big, as in IN a country: We live IN France. The statue of Liberty is IN the USA. There are many languages IN Europe. You can buy nice jewelry IN Paris. There are nice old houses IN the Bronx.
- ON is used to indicate smaller places. There is a bakery ON my street. It’s impossible to park ON this avenue. Many birds live ON the Amazon.
- AT is used to indicate very specific locations such as: I will meet you AT the intersection. She’s already AT the store. I have pet birds AT my house. You can let dogs loose AT this park.
Date and Time
The same usage of IN, ON, and AT happens with date and time.
Big: There was a lot of industrial development IN the 19th Century. I visited Africa IN 2016. I take my vacations IN July. It’s not surprising to have rain IN the first week of March.
Small: I will be in New York ON my birthday. They do fun activities ON the weekend (Watch out! They say “AT the weekend” in England). I talk to my mother ON Mondays.
Smaller: He always has a sandwich AT lunch. She drinks coffee only AT breakfast. Let’s meet AT noon.
These rules do NOT work 100% of the time. There are EXCEPTIONS such as: “in the evening”, “in the afternoon”, “in the morning”.