What human body organs are located in the epigastric region?

Lots. Lower esophagus, stomach, duodenum, gallbladder (just to the right), liver (left lobe), colon comes across, lymph nodes, occasionally pancreas symptoms, spleen (to the left; epigastrium if enlarged), aorta. Heart symptoms can present there too.
See below. Lower part of esophagus, stomach, duodenum (1st part of small intestine), pancreas, gallbladder, tip of spleen.