What's remaining of Einstein's brain is stored at Princeton Hospital in New Jersey under the care of Dr. Elliot Krauss. Dr. Thomas Harvey was the doctor who initially conducted the autopsy on Einstein at Princeton Hospital in 1955 and removed Einstein's brain, carefully sliced it into sections, and then kept it for research. According to reports, Dr. Thomas Harvey did not have permission from Einstein's family to keep his brain. After his release from Princeton, Dr. Harvey kept the brain sections stored in jars for nearly 23 years and placed the jars in a box behind a beer cooler in his office. The brain was recovered by Princeton Hospital and research results were published thereafter.
There are currently at least three (3) published papers related to Einstein's brain. These papers concluded, in-part, that Einstein's brain had more glial cells than average, had a thinner cerebral cortex and weighed less than the average human brain. However, although the cerebral cortex was thinner than others, it was found to contain a higher than average density of neurons.
Fun fact: A person that has a large brain size does not indicate that they are more intelligent than someone with a smaller brain.