Hartman Bridge, middle fork of the Rogue River
From Medford, drive north on Highway 62 to Prospect. Turn right onto one of the access roads to Mill Creek Drive, and find the historic Prospect Hotel in town (391 Mill Creek Drive). Just south of the hotel is Red Blanket Road. Take this until it makes a left turn, but go straight ahead on what is now the Butte Falls-Prospect Highway. Drive until you are about 4.0 miles from the Prospect Hotel, and park on the right in the clear area just before the bridge. The plaque is on the right side of the bridge before you cross it. You are on the Middle Fork of the Rogue River. Note how high the bridge is above the rocky river below.
Sharon Bywater has a nice article on the Hartman Family in the Southern Oregon Historical Society Quarterly, Spring 2020, page 8. According to the article, Jaston (or Jason or Justin) and two of his sons, Lyal and Wesley, were well known bridge builders in Jackson county, building over 700 bridges over a combined period of 125 years. In 1910 the family moved to Jacksonville where they resided permanently. In the early days they built covered bridges, including the Wimer, McKee and Antelope Creek Bridges. Both boys worked for Jackson County. Wesley retired in 1963 as county bridge superintendent. Lyal retired in 1969 as county bridge foreman. See also a plaque to the two brothers on East F Street on a bridge crossing Jackson Creek in Jacksonville.