"at the corner" and "on the corner" are generally interchangeable. It tells the location of something outside. For example "Our house is on/at the corner of 4th Street and Maple Street". "On/at" the corner is used to describe the location of something that is on a flat surface with no walls. For example "The glass is sitting on the corner of the table". In the corner describes the location of something that is inside. If something is in the corner, the it is located where two walls meet. "The lamp is in the corner of the room". "Write your name in the top left corner of the paper" Around the corner can refer to inside or outside. It simply means at the corner and then to the left or right. "My house is around the corner from the grocery store to the left". this means.... from your current location, you need to go to the next corner and turn left.