Bing bird's-eye view shows historic Hangar 61 at former Stapleton Airport. The unusual structure is one of tens of thousands of parcels in a DRCOG report for transportation planners.

Transportation planners are legally obligated to consider the impacts of highway or transit improvements on potentially historic sites.

It’s hard for me to think of buildings being historic when I am older than they are.

But federal law says properties older than 50 years can be evaluated for historic preservation, assuming a lot of other things are also in place such as historical, architectural or some other significance as well. I’m over 50, but the shape I’m in I have no architectural value!

But for planners, there is now a helpful tool to use when they work on transportation corridors in metro Denver.

The Denver Regional Council of Governments has put together a data-heavy report, using Geographic Information System data from all but one of the nine counties in the DRCOG region, that shows planners the locations of tens of thousands of parcels with historic-qualified properties.

It has maps of 13 freeway and 19 major arterial street corridors throughout the DRCOG region, color-coding those parcels with structures built in 1964 or earlier and located within a one-mile distance of the corridor. The only county from which GIS info wasn’t obtained was Jefferson, and that leaves a gaping hole in the doughnut.

Now, the fact that a property is highlighted on the map not mean that it is eligible for preservation. In fact, most are not and never will be. A huge number of the parcels are those of single-family homes across the metro areas many diverse neighborhoods built before 1964. Using 1964 as the stop-date gives the report a shelf life of five more years, but with the digitized data on hand it can easily be updated.

DRCOG staff had to take all of the GIS data from the various counties and reorganize it into a format that allowed them to combine them into a single data base with all of the same data fields.

The report, “Mapping Inventory of Potential Historic Parcels in the Denver Region,” is available online here. It’s a huge file, 26.5 MB, so it will take a while to download depending on the speed of your connection.

It’s easy to see from the regional map on page seven of the 41-page report what the extent of urban development was in 1964. The parcels that were built on at that time are concentrated around central Denver, close-in Adams County, Aurora along Colfax Avenue, Littleton, Englewood and some other inner suburbs.

Parcels that are old enough for historic evaluation in the Denver metro area -- minus Jefferson County's data -- are shown on this DRCOG map.

The 32 maps of freeway and arterial corridors call out only those parcels within the two-mile swath of each roadway.

The report doesn’t list the parcels that already have local, state or National Register historic status. It’s not meant to. It shows the parcels that should be evaluated for eligibility, however.

The requirement to consider the impact of federally funded transportation improvements on them stems from the National Historic Preservation Act of 1966, which set the criteria for preservation. Federal funds cannot be spent on a project without considering the impacts on these properties. That’s what drives the usefulness of the data that DRCOG has published.

A few things I gleaned from the report:

The slot for the vertical stabilizer on Ideal Basic's Fairchild F25 can be seen at the top of the hangar doors.

It’s located five blocks north of Colfax Avenue at Central Park Boulevard. It is listed on the city and the state list of historic structures.

Unsurprisingly, the report shows the corridor with the most parcels containing historic structures is East Colfax Avenue through Denver and Aurora, where 37,024 parcels contain structures built up to 1964.

The second-highest number is on the Colorado-Vasquez Boulevard corridor, from Hampden Avenue on the south to where Vasquez merges onto Interstate 76 on the north.

The third-highest number is on the Interstate 25 Southeast Corridor, with 26,591 parcels. It’s unlikely there will be much call on the data for that one, because it was upgraded during the T-REX project and shouldn’t require significant work for many years.

This is what one of the corridor pages looks like in the DRCOG report on potentially historic parcels, this one highlighting the East Colfax Corridor.

If the Jeffco parcels can be added to the data base, it would fill in the significant gaps in the Wadsworth Boulevard Corridor, which may also contain a large number of historic parcels as it goes from Broomfield on the north to C-470 near Chatfield Reservoir on the south.

Other Jefferson County corridors that need to be filled in: the proposed Northwest Parkway toll road, Hampden Avenue Freeway, Sixth Avenue Freeway, Interstate 70 West to C-470, I-70 Mountain Corridor to the Eisenhower Tunnel, which is in the DRCOG region, and the C-470 Corridor.