I-197 (cancelled)  Maryland (link)

A proposed numbering in the 1970s and 1980s for a portion of US 50/301 from I-97 toward Annapolis. I-97 itself was proposed to continue west on US 50/301 back to I-95/495 near Washington D.C., forming two sides of a triangle between Baltimore, Annapolis, and the nation's capital.

In 1978 Interstate 197 was allotted 0.8 miles [1]. In a circa 1980 plan, I-197 was listed at about 4 miles, terminating at MD 70. [4] In 1982 this was still the case, and I-197 was approved. [5] But in 1983 I-197 was removed from the plan.

Dropping I-197 makes sense, as it was just another numbering for a road that already had two (US 50 and US 301). In fact, US 50/301 is now officially I-595 between I-495 and MD 70, but is not signed as such for the same reasons.

Earlier I had written that I-197 was proposed for the MD 665 freeway south of Annapolis, but that apparently was just a rumor, gleaned from an MTR post in 1997.

See also: Non-Indiana Highways (Stephen Summers; I-197 and I-297 scans and lots of other neat stuff)

I-297 (cancelled)  Maryland (link)

A proposed freeway upgrade of MD 3 between I-97 at Millersville and US 50/301 at Bowie. This was first proposed in the 1970s, and canceled around 1990. It was part of the package with I-68/US 50 and I-97 that was approved in the mid-1980's. [2]

The I-297 numbering appears to have first surfaced around 1982. It would have been 7.7 miles long. [4] [5] [6]

In November 2002, the State Highway Administration revealed a half-dozen alternatives for improving the MD 3 corridor. None of them include a full freeway, but some include grade separations and and interchange at MD 450. [3]

Until 1983, I-97 was also proposed to follow US 50/301 from Annapolis back to I-495 at Washington, D.C. forming two sides of a triangle; then I-297 would have met I-97 twice. In 1983, the US 50/301 route proposal was changed to Interstate 68. Now, it is unsigned I-595.

See also: Non-Indiana Highways (Stephen Summers; I-297 and I-197 scans and oodles of other groovy stuff)

Sources

1. Route Log and Finder List - Interstate Highways, USDOT, 1978
2. Kozel, Scott
3. "State considers Route 3 proposals: Public comment sought on 6 plans to help ease congestion in corridor." Baltimore Sun, Nov. 12, 2002. (thanks to Scott Kozel)
4. Baltimore-Annapolis Transportation Corridor Study, scans provided by Stephen Summers
5. Environmental Impact Statement (EIS), FHWA-MD-EIS-81-01-f, scans provided by Stephen Summers
6. EIS Maryland Route 3 Corridor Study dated 7/5/1983, FHWA-MD-EIS-81-02-F, scans provided by Stephen Summers