The Yankton County Planning and Zoning Office will be open Tuesday, May 21th, 2019 from 9am-5pm, Wednesday May 22,2019 and Thursday May 23rd, 2019 from 9am-3pm. Any questions you might have outside of these hours should be directed to the Yankton County Auditor’s office on the first floor of the Government Center. Phone number 605-260-4400 ext. 0. Yankton County Auditor’s Office Hours are 9:00am-5:00pm Monday-Friday.