Through most of the Vietnam scenes we see groves of palm trees that are not found in Asia. In the foreground shots we see the Sabal palmetto (a.k.a. the Cabbage Palm). Sabal is a genus of New World palms, exclusively. This distinctive palm thrives in its native range where the Vietnam parts of the film were actually shot - in South Carolina, which also bears this palm on their state flag. Background matte paintings or computer graphics may fill in related scenes accurately, but the Sabal palms we see betrays the movie's depicted location of Vietnam.
When Forrest begins his three-year run, as he passes the barbershop in town, the TV announcer says President Jimmy Carter suffered from heat exhaustion. That happened on September 15, 1979. However, Forrest begins his trip presumably on July 5, 1976, when Carter isn't President yet.
When Forrest and Bubba get off the helicopter upon arriving in Vietnam, they stare at a big pile of beer cans that someone is stacking up nearby. The tops of the beer cans are clearly visible with pull tabs, a feature that was not available on any cans during the Viet Nam era.
Using George Wallace symbolic blocking of the doorway to the University of Alabama (11 June 1963) as a time reference, we know that Forrest is named to the college football All-America team in 1963 where he later meets John F. Kennedy. However, the Associated Press announced their All-America team on 6 Dec 1963 - two weeks after JFK was assassinated. Forrest Gump should never have met JFK.
The letter from Apple Computer, dated 1975, uses the 'Apple Garamond' font below the logo. Apple did not use this font before the introduction of the Macintosh in 1984. Until then, the logo featured the Motter Tektura font. The Garamond font itself was only designed in 1977.
When Forrest is playing ping-pong before being discharged, the gymnasium where he's playing shows the 3-point line on the basketball court. The 3-point line was first used 29 November 1980 in a college basketball game at Reid Gym in Cullowhee, North Carolina.
The film suggests that Forrest Gump inspired the happy face logo in the late 1970s. Although there is dispute as to when and who originated the smiley face (sometime in the mid 1960s) it was being commonly used in the early 1970s by brothers Murray and Bernard Spain, who used the image in a campaign to sell novelty items such as pin back buttons. The smiley face had already passed its peak of popularity by the late 1970s when the film suggests it was first created.
When they are patrolling along the road in Vietnam, several of the soldiers are seen carrying poncho liners made out of woodland camouflage pattern material. This specific pattern did not appear on U.S. uniforms and equipment until the mid-1980s.
The Stroh's neon beer sign shown outside the Times Square bar in the early 70's, is a blue, block lettered logo. This logo did not appear until the mid-late 80's. They used a red-script logo up until that time.
Through out the film Lt. Dan refers to Forrest as Private Gump, despite him achieving the rank of Sergeant at the time of his discharge (signified by the patch on his sleeve). The officer giving Forrest his discharge also makes the same mistake by calling him "Private Gump" even though he is wearing sergeant stripes on his uniform.
Prior to the Medal of Honor ceremony at the White House, a newsman announces that four service members, one from each service, are being awarded the Medal. When Forrest bends over to show President Lyndon Johnson his wound, there are four members from each of the services with the Medal around their necks, meaning that Forrest makes five.
On seeing Gump on the shrimp boat, Lt. Dan says, "they gave you the Congressional Medal of Honor?"
The medal is frequently, albeit incorrectly, called the Congressional Medal of Honor, stemming from its award by the Department of Defense "in the name of Congress." It is correctly the "Medal of Honor".
Around the 1:24:00 mark, Forrest is recovering from being shot in buttock. He is sitting in a chair watching the guys play ping-pong. Behind one of the guys playing ping pong, you can see "Lt. Dan's" character sitting in back ground smoking a cigarette with his legs crossed. That is not possible as Lt. Dan's legs were amputated.
When Forrest is in the hospital with a butt injury, he is given back all the letters he wrote to Jenny. On the first envelope, the zip code of her address is 39902. On the second envelope, the zip code is 96602. The third and remaining zip codes are again 39902.
During the Protest Rally at the Washington Monument, the tree leaves are not consistent. Behind Forrest on the podium, the trees in the background have no leaves as if it were late autumn or winter. The trees surrounding the reflection pool in front of Forrest are all Green as if it were summer, and in a later scene as Forrest watches Jenny board the bus back to Berkeley, the leaves on all the trees are different colors as if it were the heart of autumn.
In the scene where Forrest sees Lt. Dan on the dock and jumps from his shrimping boat to meet him, the boat is moving right in the point of view of Lt. Dan. However, when the boat crashes, it had been moving left, impossible in such a short amount of time without a person steering it.
Forrest can't run with his braces; he can barely walk. When he and Jenny run to their favorite tree, he is running normally. Yet when the bullies from school chase him on their bikes, he is back to his old gait. It is only after the braces are lost that he runs normally.
Forrest is standing in Jenny's foyer upon entry to her apartment. While they are talking it's possible to see in the background there is an ironing board with the iron laying flat, as if it had been knocked over. While screen shot quickly focuses on the son watching television then quickly back to Forrest and Jenny, the iron has been stood up correctly. Forrest and Jenny had not moved.
On the boat, Lt. Dan says he never thanked Forrest for saving his life. Immediately after that he swivels round on the deck and jumps into the water. At that point, the water is flat calm, but when the camera cuts immediately to Lt. Dan doing a backstroke away from the boat, the water is quite choppy.
When Forrest and Jenny are "walking" along past a candlelit vigil in front of the White House, it is noticeable that they pass the same five or six people several times (as well as a couple of the guards at the gate).
When the number 4 bus arrives for the first woman that Forrest talked to on the bench, the bus takes off right when she exits the frame, clearly not giving her enough time to board it. Since only a small portion of the end of the bus is shown, the bus would have had to wait a couple more seconds for the woman to walk to the front of the bus and then board it.
In the final scene of the movie, Forrest's wedding ring vanishes between shots. When he is admiring the Curious George Book, his wedding ring is present. After Forrest Jr. gets on the school bus, and Forrest Sr. sits back down on the tree stump and the camera pans to the feather on the ground, the ring vanishes.
When Lt. Dan calls in the air strike, there are 2 soldiers to his right, then there is an explosion and sudden fireball (supposedly killing the 2 soldiers). After the explosion, the next scene shows an M-16 being fired from that position (the person firing it is not seen).
When Lt. Dan meets Forrest after Forrest becomes a shrimp boat captain, Lt. Dan smokes a cigar. The ash on the end of the cigar changes between shots; it's longer when the camera is facing Forrest than when the camera is facing Lt. Dan.
At the Black Panther office in DC, after Jenny's boyfriend smacks her and Forrest attacks him, the two of them slide off of a table onto the floor fighting. When they cut away, then back to the fight, the now-collapsed table is under them.
Around the 6 minute mark when Forrest and his mom are crossing the street, the same black truck in the background passes them twice, before his foot gets caught in the sewer grate and right after, after the camera cuts to a different view.
The tempo in the first song, when he is running, "running on empty," speeds up and slows down. You can tell they edited the clips together. The scenes or the music must have been sped up or slowed down.
When Forrest and Lieutenant Dan are celebrating New Years Eve in the New York City at a bar, Forrest is thinking about Jenny out in California. The ball is dropping on TV and everyone is counting down to the New Year in New York, the scene then cuts to Jenny out in California and she is packing her stuff and leaving the house she's at and as she walks out the door the ball is also dropping and counting down to the New Year on the TV. But New York and California are in very different time zones, it wouldn't have been the New Year for Jenny in California for several more hours.
In the final scene the school bus pulls away leaving Forrest on the right and a line of white mail boxes to the left. Three of the mail boxes have round blue containers to put rolled up newspapers in attached to them. Between the bus departing shot and the white feather shot a newspaper appears and disappears in the blue container on the far left.
While Gump is playing ping pong, a man comes up asking for a PFC Gump (E-3) to notify him he has been awarded the Medal of Honor. In the following scene when he is in DC to be awarded his medal, he is wearing the rank of sergeant (E-5). While it's possible he was promoted between the two scenes, he certainly wouldn't have been promoted two ranks, and at most would have been an E-4 (Specialist or corporal).
In the final scene as young Forrest is waiting for the bus, he opens Curious George and talks about how his Grandmother read this book to him. But, both Grandmothers were dead before young Forrest was conceived.
When Forest is playing football for Alabama, a teammate gives him the ball and he runs for a touchdown. The hand-off was a forward which is illegal on a kicking play. This should have been a penalty and the touchdown would not count.
When SGT Forrest Gump receives his LOD (Letter of Discharge), he is only wearing five ribbons - Purple Heart, Army Good Conduct Medal, National Defense Service Medal, Vietnam Service Medal, and the Republic of Vietnam Medal, but is missing the ribbon device for the Medal of Honor for which he was awarded by President Lyndon Johnson There is a ribbon as well as the neck medal for the Medal of Honor. His ribbon rack is missing the MOH ribbon.
During the integration of the University of Alabama, the soldiers escorting the black students are depicted as paratroopers from the 82nd Airborne Division. This was actually performed by the Alabama National Guard, after they put under direct federal control by President John F. Kennedy.
In the end credits section where the producers wish to thank companies that provided assistance, Dr Pepper is incorrectly listed as Dr. Pepper (with the period). It hasn't had a period in its name since the 1950s.
The original tropical jackets in Vietnam era had a much smaller collar length, more like a shirt collar measuring no more than 3.5 inch, while the jackets appeared in the movie were sewn with a much longer collar.
Several inaccuracies in the military uniforms crop up in the film. Ribbons out of order, the wrong style of helmet, the wrong collar, etcetera. These are simply mistakes. There is no law in the USA for military uniforms in movies to be incorrect in order to avoid "impersonation." They simply got things wrong.
Car tire tracks are visible in the segment remembering Nathan Bedford Forrest's Civil War ties with the KKK. However, this footage is taken from D.W. Griffith's The Birth of a Nation, and the CG team chose to leave the goof in.
Forrest and Bubba clearly state to Lt. Dan upon meeting him for the first time that they are from Alabama, but, shortly afterward, Lt. Dan says, "So you boys are from Arkansas, huh?" (Given how he acts for most of the movie, it's possible Lt. Dan probably wasn't paying any attention.)
When Forrest sits on the bench by the square and the bus passes him, the traffic is going in the wrong direction. In Savannah, traffic goes counter-clockwise round city squares. (The flow was reversed for the movie in order to have the bus doors open into the square.)
In the montage of Forrest's and Lt. Dan's first successful shrimp catch after the hurricane where they are emptying their full shrimp nets onto the deck of the boat, the shrimp nets are full of headless shrimp. Shrimp caught in nets are complete animals, and they are processed on the boat after they are dumped, at which time their heads are removed. Shrimp boats do not catch pre-processed shrimp from the waters of the gulf.
When Forrest is given his discharge papers, he sets down his ping-pong paddle and (computerized) ball to salute the officer. When he picks the paddle back up, he also pretends to pick up the ball, which didn't end up getting animated.
When Forrest is playing ping pong, the computerized ball starts moving very quickly. If you follow it closely, you can see that it bounces off his elbow at one point instead of the paddle (right before the ball bounces and then seems to hit the camera).