Please see the links on the US Geography Championships website here for results from the National Qualifying Exams (note that the same exams are used for the USGC and the International Geography Bee).

Results for the International Geography Bee Regional Quiz Tournaments in the USA are available here.

2019 International Geography Bee US National Championships Results
National Champions
Varsity: Karan Menon, J.P. Stevens High School, Edison, NJ
Junior Varsity: Samvrit Rao, Stone Hill Middle School, Ashburn, VA

8th Grade: Rishabh Wuppalapati, Daniel Wright Junior High School, Lincolnshire, IL
7th Grade: Kaylan Patel, Windermere Preparatory School, Windermere, FL
6th Grade: Vaibhav Hariram, Mills Park Middle School, Cary, NC
Elementary School: Pranavkrishna Bharanidharan, California Montessori Project, Orangevale, CA

2019 Varsity and Junior Varsity National Championship Statistics are available at this link here.
2019 Middle School and Elementary National Championships Statistics are available at this link here.

2018 International Geography Bee US National Championships Results
National Champions
Varsity: Alex Schmidt, Lehigh Valley Academy, Pennsylvania
Junior Varsity: Samanyu Dixit, Metrolina Regional School, North Carolina

Middle School
Samik Bhinge, Frost Middle School, Virginia (Overall and 7th Grade Classification)
Samanyu Dixit, Metrolina Regional School, North Carolina (8th Grade Classification)

Elementary
Rohan Ganeshan, Homeschool, Illinois (Overall and 6th Grade Classification)
John Augustyn, Notre Dame School, Illinois (5th Grade Classification)
Anish Raja, Brookwood Elementary School, Georgia (4th Grade and Younger Classification)

2018 Varsity and Junior Varsity National Championship Statistics are available at this link here.
2018 Middle School and Elementary National Championships Statistics are available at this link here.

2017 International Geography Bee US National Championships Results
National Champions
Varsity: Jakob Myers, Naperville North High School, Naperville, Illinois
Junior Varsity: Rohil Bhinge, Frost Middle School, Fairfax, Virginia
Middle School: Saket Pochiraju, Olentangy Orange Middle School, Lewis Center, Ohio
Elementary: Satvik Pochiraju, Olentangy Meadows Elementary School, Lewis Center, Ohio

2017 Varsity and Junior Varsity National Championship Statistics are available at this link here.
2017 Middle School and Elementary National Championships Statistics are available at this link here.