Factual error: In the early scene where Dennis Nedry meets a man to plan the embryo theft, the subtitle says that they are in San Jose, Costa Rica. However, the sleepy coastal town in the movie bears no resemblance to the real San Jose (a cosmopolitan capital of almost 1 million people, situated 50 miles from either coast).
Factual error: When the doctor is showing off the piece of amber that they have gotten the DNA from, there is a problem. The mosquito in the amber is a male, as one can tell by the antennae. Because it is only the female mosquito that feeds on blood, the male should only have nectar in its stomach. To make it worse, in that species of mosquito, Toxirhynchites, both the males AND females are flower feeders, and would therefore have no blood, or dinosaur DNA in their stomachs.