It's better for everyone.
It's about building relationships and knowing where your food comes from. It's about running into your neighbor on a sunny summer afternoon. It's about breaking bread with friends, sharing a steaming plate of greens, verdant salads, vivid orange carrots and flaming peppers, all grown by people you know. Besides these things, your food requires less fossil fuels and emissions to get to you, and you can rest assured that the people who grew what you eat were paid fare wages and were not exposed to pesticides. Everyone wins.
Supporting local farmers will keep land in the hands of the people who have tended it for generations. Keeping money in nearby communities strengthens rural communities.
Supporting local farmers through shopping at a farmers' market cuts down on the miles your food travels from where it is grown to your plate. The average grocery store's produce in the United States travels 1,500 miles from the farm to your plate. All of this traveling on freighters, airplanes and trucks takes plenty of fossil fuels. Supporting local farmers means you'll be using less packaging and shipping materials. It also means you'll be supporting people who care about their land and water.

Cincinnati Locavore blog- named Cincinnati's best by Citybeat in 2008!