You must file your case in the County in which the Defendant (the party you are suing) resides. This requirement is referred to as "venue."
Individual - For an individual, venue is the County of the person's legal residence.
Businesses - The type of business determines the proper venue for a business named as the defendant. For a sole proprietorship, the suit should be filed in the county in which the owner of the business resides. For a partnership, the suit should be filed in the county in which at least one of the owners resides. For a corporation, the suit should be filed in the county where the corporation has designated its registered office with the Secretary of State’s Office.
Multiple Defendants - For multiple defendants, you can file your case in any County in which venue would be proper for at least one of the defendants, if they are jointly and severally liable.