Hexagonal boron nitride (h-BN) is a high temperature ceramic material with a graphite-like layered atomic arrangement and excellent basal-plane thermal conduction properties. Unlike graphite, however, h-BN is electrically insulating and possesses superior chemical stability, thereby making it attractive for many applications for which carbon allotropes are not suitable. In this work, freestanding three-dimensional foam-like h-BN nanomaterials tens of millimeters in size are realized by a low-cost atmospheric pressure chemical vapor deposition (APCVD) process. These three-dimensional foams were found to be ultralight with an effective density of 1.7 +/- A 0.6 mg/cm(3). Strut wall thicknesses were observed to be 311 +/- A 82 nm, significantly thicker than reported in previous works using alternative CVD approaches. The samples were further analyzed using Raman spectroscopy, electron beam energy dispersive spectroscopy, and X-ray diffraction revealing the samples to exhibit characteristics consistent with h-BN. APCVD processes like the one presented here may provide a simple, scalable means of realizing ultralight hierarchical h-BN nanomaterials with tunable mechanical and thermal properties.