Table 1. Disease transmission routes in the model.

	Movement spread*	Non-movement spread
		Within-county	Local cross-border
Cause	Animal Shipments	Aerosol, fence-line contact, or fomite transmission	Aerosol, fence-line contact, or fomite transmission
Spatial Scale	All counties in the US	Premises within an infected county	All neighboring counties
Assumptions	1) Premises density-dependent; 2)Spatially explicit†; 3)Differs by state and production type	1) Premises density-dependent; 2)Premises size dependent	1) Premises density-dependent‡; 2)Premises size dependent‡; 3) Spatially implicit§
Informed by or data from	1) ICVI records; 2) Number of premises by county and production type¶; 3) State cattle inflows [38]	1) 2001 UK FMD outbreak [39]; 2) US premises density and size distributions¶	1) 2001 UK FMD outbreak [39]; 2) US premises density and size distributions ¶; 3) Shared county border length
Parameter Uncertainty	Estimated through Bayesian inference and incorporated in the simulations via multiple realizations of shipment networks.	Broad parameter ranges explored in a sensitivity analysis||.	Broad parameter ranges explored in a sensitivity analysis||.

*See Section C in Text S1 and Lindström et al. [24].

^†Based on county centroids.

^‡In both the focal and neighboring counties.

^§Based on randomly distributed premises in the focal and neighboring counties.

^¶See Section B in Text S1 and NASS census data [15].

^||See Section E in Text S1.