Historic US highway 6 through Georgetown and Silver Plume, Colorado
Detail from 1950's Carter Oil Company map of "Denver Mountain Parks"
The little town of Silver Plume (elevation 9118') occupies a wide spot in the upper Clear Creek valley. Georgetown is less than two miles to the east, but by that point the stream has dropped by 600 feet (elevation 8519'). Consequently, transportation through that reach of the valley has always posed challenges. In 1884 the railroad solved the problem by designing the famous "Georgetown Loop". Its grade was such that trains could get up the valley, but the length of the tracks between the two towns measured over four miles (on the USGS map below, I've highlighted its route in red). Later, after automobiles had been invented, drivers heading up the valley on US 6 had to negotiate their first switchbacks between Georgetown and Silver Plume (see Carter map above, and yellow line on map below). When Interstate 70 was built through the area in the late 1960s, the switchbacks were eliminated, but now that stretch is one of the most difficult uphill grades for westbound traffic (purple line).
Today, between Silver Plume and Georgetown, there is a scenic pullout off I-70 (accessible to eastbound traffic only). During warmer months, it serves as a good perch from which to view the old train running between the two towns along the reconstructed Georgetown Loop Railroad. You can see it on the enlarged portion of the map below, just above the label for "Lebanon Tunnel".
Running through this pullout is a paved biking/walking trail connecting the two towns; heading eastward from the parking area, it essentially follows the path of original US 6 down to the parking lot for the Railroad. The photo below was taken from that trail, and it gives a pretty good overview of the whole story. We're looking eastward (downstream) in the Clear Creek valley; Georgetown itself is hidden behind the trees at (A).
I-70 runs just off the left side of the photo. Original US 6 sat on the same roadbed - but up ahead, traffic veered off onto the old grade, still visible at (B). Behind the trees at (C) was the upper switchback, and then the road came back upstream (D). It crossed under the railroad bridge at (E), reappearing from behind the trees at (F). Today the parking lot for the Loop Railroad (G) sits inside the "U" formed by the lower switchback (H). Old US 6 now serves only as an access road for this parking lot; it continues downvalley towards Georgetown at (J).
The railroad is interesting, too. Trains coming up from Georgetown were on the far side of Clear Creek, down in the valley at (V), continuing off the right edge of the photo. After about a half-mile, the tracks crossed the stream and headed back this way along the near side of the valley (in the downstream direction, but still gaining elevation). The railroad is at (W), reappearing from behind the hillside at (X). By the time the train crossed over its own track via the Devils Gate Bridge (Y), it had gained nearly 100 feet in elevation. It had already travelled over a mile, but still had over three more towards (Z) to get to Silver Plume! The Railroad's website has lots more info, photos, and a comprehensive history.
In the photo below, we've moved slightly ahead (east) on the recreational trail. This is the point where westbound US 6 rose to the level of what would later become I-70 (the portion of I-70 visible at far left didn't exist until about 1968). Here, the rec trail sits on top of the old US 6 roadbed (K), heading towards the upper switchback.
There's also evidence of another roadbed (L) which I believe was used only temporarily, during the construction of I-70. I arrived at this conclusion based on the USGS map shown above (enlarged below). The original basemap was drawn in 1957; it used black casing for the roadlines. The map was revised and reprinted in 1974 (based on aerial photos taken the same year) using purple ink for changes. Note how I-70 was included in this revision; note also how the original black casing for most of US 6's upper switchback was removed, and instead there is a road with purple casing there.
I believe the original route of US 6 was along the yellow line, and that this USGS map captured a very temporary situation in the transportation history of this valley. Those familiar with the revision schedule for USGS quads will understand the odds against a map of this type depicting such a brief moment in time.
In the photo below, the view is back upvalley. Silver Plume is behind the mountainside at (M), about a mile distant. I-70 and the rec trail are at (N). The trail loops around off the right side of the photo to the upper switchback, and comes back in at (O); that would've been the path of old US 6. During the construction of I-70, the temporary grade came down at (P) to a new upper switchback at (Q) and continued downhill via (R).
You can just make out the railroad bridge in the distance (S). Along the edge of the road at (T), some of the old guardrail posts still exist. The photo below shows one of those, with Georgetown visible down in the valley.
The next two photos were shot from the train as it was going over the high bridge. This first one is looking upvalley:
You can see the lower switchback and the parking lot it now serves. Maybe 30 feet up the slope from the parking lot is the railroad grade (the same segment labeled "W" and "X" in the photo above). The roadcut above that is I-70/old US 6. In the distance at upper left, you might just be able to make out some cars: those are parked at the aforementioned scenic pullout.
The photo below is from the same spot, but looking downvalley. Georgetown is visible at upper right; the road is old US 6 coming up from there. After the lower switchback shown above, the road continued along the path visible at upper left - you can just see the upper switchback there.
If you continue to the far (upper) edge of the parking lot, you can see some of the old pavement for US 6 (below):
That's between the two switchbacks, so it's looking east from the perspective of a westbound driver. The high bridge was reconstructed recently (mid-1980s I think), and now the embankment at left sits on top of the old US 6 right-of-way. In the photo below, I was standing on the other side of that embankment, looking the same direction:
You can still see the old centerline stripe, as well as some of the aforementioned guardrail posts. Incidentally, the rust-colored spots visible on some of these mountainsides are tailings from gold mines; there were many silver mines in the area too.
The original roadbed used by US 6 now carries I-70 between the upper switchback and Silver Plume (exit 226). There, I-70 veers slightly south, and old US 6 now serves as the offramp for westbound traffic.
At the stop sign, most people go left under I-70 to the Railroad parking area. Others turn right, towards "downtown" Silver Plume. But to go straight is to continue west on the original US 6 through town. After about a mile, the road crosses under I-70 and then runs parallel to it along the opposite bank of Clear Creek:
It's a local access road westward to Bakerville (exit 221), and it's probably the best way to get a feel for what it was like to drive old US 6 though these parts. But none of it actually was US 6; the original highway was on the north bank of Clear Creek, and now it's covered by I-70 between west Silver Plume and Loveland Pass (exit 216). In the photo above, old US 6 would've continued straight ahead (through the "road closed" barricade), curving to the right on what is now I-70's roadbed.
I just happened to see this sign through a Silver Plume storefront window as I was driving along Main Street in summer 2002. I was hoping it was an antique store, but as it turned out the sign was serving as decor on the wall of a little cafe. Here's a close-up of the shield (which was no longer there as of summer 2003):
Back when that marker was posted on the road, US 6 was the longest highway in the country. You can read about its current and historic endpoints here.