Yup Hayti, South Dakota population 362, there's the reason for the 4 digit phone number! I had relatives who lived in Grand Tower Illinios back in the 1950's, 60's and into the early 70's when you called around town it was a 3 digit number, so the number of digits depended on how big the population was. when you called any distance then it was for example HU (HUDSON) 32700 and that would be Chicago