Eighteen months ago, I blogged about 54 applications filed in the twentieth century at the USPTO that were still pending. Now, in May of 2018, there are still 35 pending applications from last century.
Most of these are likely suspended due to ongoing litigation or oppositions filed regarding the applied-for marks or other marks that the USPTO examiner has viewed as a potential conflict. It is safe to say, that since they are pending more than 17 years, they all have interesting and complex histories.
Based on the Serial Numbers, it appears the oldest pending application with the USPTO is for (SN 74365176). The application was filed in March of 1993, more than 25 years ago!
Tip: experienced counsel, trademark docketing software, and knowledge of the USPTO trademark application process are very valuable when filing any trademark application — because you never know how long that application may last!