In Iowa, milepost markers aren't just for Interstate highways. They're also used along most US and state highways. Where highways are multiplexed, as along US 63 and Iowa 2 west of Bloomfield, a miniature marker is placed atop the mileage marker to indicate the highway for which the marker is counting the miles. For north-south highways such as US 63, mileage is counted from south to north. (East-west highways count mileage from west to east.) So, at this point, you're 12 miles from the Missouri border on US 63.