Spangenberg qualified for National competition in two events after impressive performances during the Regional and Zone Championship shows earlier this season.
Spangenberg faced tough competition at Nationals, but said she was very pleased with her results.
Spangenberg first competed in Novice Over Fences, where she earned a score of 82 to put her third in the individual competition behind Julie Connors of Centenary College and Sarah Jarosinski of Hollins University.
She took third again in her second event of the day in the On the Flat event, falling behind Hanae Kimura of Skidmore College and Carly Ziegler of George Mason University.
The National Championship takes great care not only in choosing the horses for the events, but in ensuring equity across the field for all riders in every event, according to Spangenberg.
The horse's quality is very important to a rider's success, and Spangenberg said she was pleased with the abilities of her two horses.
"I ended up with great [horse] draws for both classes," she said in an email to The Dartmouth.
Spangenberg is the first Big Green rider to compete at the National Championship Show since Samantha Parsons '10 in 2009.
Her third place finishes mark the best showing at a National Championship event ever by a member of the Dartmouth equestrian team.
Spangenberg qualified for the National Show in both of her classes a feat that has rarely been achieved in the history of the program.
"Only a few riders qualified in both of their possible classes, so I was excited simply to be going to Nationals in both," she said.
Fellow rider Faye Keegan '12 noted the importance of Spangenberg to the equestrian team as a senior leader.
"The team is so proud to have her as a member," she said. "She's an integral part of our team."
Spangenberg's talent as a rider contributed to the overall accomplishments of the team throughout the season, according to Keegan.
"She's a beautiful rider," Keegan said. "She's been a natural leader on the team."
Spangenberg's experience at Nationals wraps up her collegiate equestrian career, and she said she was excited that her last show as a Dartmouth rider was on such a big stage.
"Since it is my senior year and my last show as a collegiate rider, I was really hoping to do well," she said. "It was a great way to end the season and a great experience to compete at such a high level against some really tough competition."
