We often get asked what a posterboard should look like. The NHSEE guidelines are basically the same as those of ISEF.
Maximum size of Project: Depth (Front to back): 30 inches or 76 centimeters; Width (side to side): 48 inches or 122 centimeters; Height (from top of table to top of display): 72 inches or 173 centimeters (tables are 30 inches or 76 centimeters high)
The upper portion of the display should include the title of the project. The display should NOT include the name of the school.
The background and sides of the project display can be put on a poster board (bi-fold; tri-fold; etc). Items on the display board could include graphs, charts, photographs, etc that provide info and help explain the project.
The following should also be at the project site so they can be checked by judges: Research Plan, Notebook, Abstract, Statement of Conclusion.