The upper northern region of Thailand are geographically characterized by multiple mountain ranges with associated fluorite deposits. Ma Khuea Chae sub-district, Muang Lamphun province was a place which found the highest concentration of fluoride in drinking water. The objectives were to examine the urinary fluoride (UF) in terms of age group and villages. The research design was descriptive research. The urine samples of 405 of village health volunteers(VHV) in the contaminated areas including 21 villages were collected. The investigated instrument was analyzed by using Ion Selective Electrode. The descriptive statistics was used to analyze including percentage, mean and SD. The result showed that the majority of population was; female, the age group between 51 - 60 years old, Resided in areas since birth, living more than 10 years, graduation of elementary school, employees, income during the 5,001 to 10,000 baht. The total mean of urinary fluoride in the VHV was 3.45 mg/L. The 13 villages of 21 villages, age group of 45 – 59 years old, and more than 60 years old had fluoride in urine higher than the standard of fluoride in urine.