http://www.ext.colostate.edu/ptlk/1201.html suggests these apples for Colorado: Cox Orange, Red Delicious, Golden Delicious, McIntosh, Jonathan, Fameuse, Northwest Greening, Joyce, Wealthy, Lodi and Haralson.  Dr. O’Connor said the cultivars listed in the #1201 Colorado State University bulletin are “typically for fresh eating but there are many possible choices.”  She also wrote to me that she knows of no website that does apple identification specific to Colorado.

I showed your pictures to a Master Gardener who is also an insurance claims adjuster for fruit tree orchards.  He could not positively identify your apples either. 

One new extension agent took a stab at it, guessing it might be an ORANGE PIPPIN, but her experience is from a south-central state. 

This seems so simple: what do your mother and father say they planted decades ago?

In order to increase the amount of usable apple, you may want to check out this information about the damage codling moth worms cause to apple flesh: http://www.ext.colostate.edu/ptlk/1201.html  Removing fallen leaves and fallen apples would be a good idea in any case.

Thank you for your wonderful reply and also going above and beyond by trying by bring other knowledgeable people into identifying this apple. It is sad but true to say, that it is hard to find much of this commitment in our world today.

I believe the Orange Pippen is probably the closest to what I've seen for a type that looks and has qualities most like it.

I remember as a little girl my grandfather bringing this tree out to be planted. He, and both my parents are now deceased and I have no other options for asking someone what type it is.

Again, THANK YOU for getting back to me with much enthusiasm.

I also wanted to let you know that I have contacted a person through the Larimer County extension about grafting classes and will hope to create some trees from this beautifully old, lone survivor.

Stacy Brown