Each year, approximately 30,000 cases of Lyme disease are reported to CDC by state health departments and the District of Columbia. However, this number does not reflect every case of Lyme disease that is diagnosed in the United States every year. Recent estimates using other methods suggest that approximately 300,000 people may get Lyme disease each year in the United States.

Reference: https://www.cdc.gov/lyme/resources/reportedcasesoflymedisease_2017-P.pdf