Historical clue formulations

• Old long-haul hwy. from Detroit to Seattle — 2025-04-16
• Hwy. that includes a Lake Michigan ferry crossing — 2024-09-29
• Hwy. through Fargo and St. Paul — 2021-07-02
• Hwy. through St. Paul, Minn. — 2020-10-09
• North Dakota-to-Michigan hwy. — 2018-03-18
• Hwy. through Minnesota, Wisconsin and Michigan — 2016-06-28
• Hwy. cut into two parts by Lake Michigan — 2015-04-21
• Old hwy. from Detroit to Seattle — 2009-02-26
• Rte. that crosses Lake Michigan by ferry — 2006-06-16
• East-west road through St. Paul — 1997-08-30