Blue US passport with gold seal, creased back cover

I lost my blue US passport yesterday around 3pm while I was walking along Main Street near the Missouri Riverfront by the South Dakota State Capitol in Pierre. It's a standard navy-blue cover with the gold eagle crest; the back cover has a small coffee ring and the bottom-right corner is a bit frayed. Inside are the photo page and personal data page, and I was counting on it for an upcoming trip next week. This passport means a lot to me -- it's how I identify myself while traveling and it holds some of my oldest travel memories tucked in the pages. If someone found it, I would really appreciate getting it back.