Congress knives date back to the early to mid 19th century.  The handles on these knives are like an equal end pen knife with an upward curve in the middle.  Most of these knives have four blades but there were also two blade (half congress) versions and whittler patterns.  There are some congress knives that are referred to as tobacco knives which is usually stamped on the main blade.  Common blades on these knives include sheepsfoot, spear, pen, coping and nail file blades.

Case XX USA congress knife
Case XX USA (1965-69) congress knife

These knives were a bit fancier then other patterns and usually feature pearl, stag and bone handles.  The Case XX models with bone (6488) and stag (5488) stag handles are very collectible.  I appreciate any traffic from the following links as I earn a commission when an item is purchased, at no extra cost to you.