Previous research has analyzed the connection between maximum SST, minimum SLP and the location and strength of the ITCZ. This study investigates the physical mechanisms that determine the location and strength of the ITCZ over land. Unlike the ITCZ over the oceans, the ITCZ over the tropical continents is dependant on the moisture available to the boundary layer through soil and vegetation. Through data analysis, parameters that have the strongest influence on the ITCZ variability are determined with NCEP OLR data used as a proxy for tropical convection. Wavelet analysis is used to separate the spectral bands of ITCZ variability into interannual, intraseasonal and high frequency variability. Statistical methods such as canonical correlation analysis are used to determine the linkages to regional parameters including vegetation cover and soil moisture, surface air temperature and pressure. Strong seasonal variability of surface temperature and pressure over land and gradients at the land-ocean boundaries may play a role in the ITCZ formation over land. Comparisons are made of the ITCZ development over South America, Africa and South Asia and theories of the development and intensity of convection over the oceans. Using a regional atmospheric model, local and non-local physical mechanisms of ITCZ formation are tested. The effect of anticyclonic absolute vorticity leading to inertial instability and the development of atmospheric convection, as proposed in studies of the ITCZ over the oceans, is analyzed in this context.