I'm not a huge Trilobite guy but I've been wanting an Olenellus for a while. Recently I had the opportunity to acquire one from the Lower Cambrian aged Pioche formation in Nevada. This is an Olenellus chiefensis and it's about 2cm long and 1.25cm wide.
The Pioche formation is known for a host of lower Cambrian trilobites and I've heard there are accessible locations to collect from it but I've not yet had the chance to do so. My desire for an Olenellus stems from the fact that there used to be a locality in Lancaster county, Pennsylvania where you could find them in the Kinzers formation. Sadly that site is now in the middle of suburban sprawl and long since obliterated.