International agreements and increased public scrutiny have resulted in the need for science-based forest inventory and monitoring systems at the national or subnational level in many countries of the world. The National Inventory and Monitoring Applications Center (NIMAC), which is a component of the Forest Service's Forest Inventory and Analysis (FIA) Program, has developed statistically based tools such as the Design Tool and Inventory and Monitoring (DTIM), and technical guidance that provides step-by-step instructions for conducting inventory design and data processing activities. With funding from the Forest Service's Office of International Programs, NIMAC has worked in countries such as Mexico, Peru, Colombia, Ecuador, Honduras, Democratic Republic of Congo, and Vietnam so far. International assistance is provided during technical visits to the countries and study tours to the United States. NIMAC also supports inventory design and implementation on the Forest Service's National Forest System and state lands as well, especially at the mid-scale where monitoring is more intensive and localized than with FIA. The chosen inventory designs meet customer needs in a cost-effective way using the best available science.