This is actually “old” news but at a recent georeferencing workshop we gave, I was in the awkward position of having an outdated slide! As posted here under the Map Tools tab, we recommend Google Maps as an efficient and easy georeferencing tool to affix coordinates to a site. Further, we used to suggest third-party mapplets to enhance these tasks. My favorites were: Lat/Long Tool, and just for fun, Dig a Hole Through Earth. I used the former a lot since you can create a nice long list of coordinates in any format you need (DMS, DD, etc) then copy/paste them all into a spreadsheet of your localities. However, Google decided to deprecate the whole program of independent developers adding in Google Maps functionality and instead shove them onto little websites of their own.
California Highways: Everything You Ever Wanted To Know About Numbered Highways. “Dumb as a post” Anyone who slings that insult around hasn’t had to georeference a common locality type in natural history collections, those based on road mileage, specifically referring to milepost on the highways and byways of the US.
Recently the Georef Team had a few based on California county road mile markers: “near 14 mile marker, Carmel Valley Road, Carmel Valley” and “Mile Marker 19.5 on Carmel Valley Rd.” to list just two on the same road. When out in the field, especially finding a noteworthy roadkill or walking along the road looking for stream confluences, it is convenient to use the landscape and mile markers to record your locality (and the GPS is packed up!), so these are far from rare in some collections. However, it’s a landmark that is not necessarily easy to georeference without a spatial database of mile markers. What? California does not have one!