Police are appealing for the driver of a small green car to make contact, after a woman was thrown from her horse in Goulceby Road, in the hamlet of Ranby.
The incident happened at around 11.30am on Saturday September 17. The woman later attended hospital for her injuries which were not life-threatening.
A woman driver stopped at the time of the incident but her details were not left.
Police would like to speak to the woman, and to any witnesses, to ascertain if she was driving too close or too fast in relation to the horse and rider.
Lincolnshire Police would like to remind drivers of the need to exercise caution when passing a horse and rider.
Nationally, 11 horse riders were killed and 116 seriously injured in collisions with motor vehicles between 2010-2015.
Drivers are asked to slow right down, not to rev their engines or use their horns, and to allow a two metre space between their car and the horse.
Further advice for drivers and riders can be found at the government’s Think! website.
• If you have any information about the incident in Ranby, call 101 and quote incident number 186 of September 17.