Lake County Residents? Prior to 1860, in Lake County, by federal law, an applicant could go to any court of record that had a seal, kept records, and had a clerk. After 1860, although the law had not changed, applicants were mostly steered to Probate Court. After 1906, the law changed and Common Pleas Court was the sole court in Lake County selected to do this task. They carried on until about 1975. After that point, Lake Countians were required to go through the Immigration and Naturalization Service (INS) in Cleveland. Many of the INS records are being stored at the National Archives regional facility in Chicago.