Micromachined packaging is emerging as the best choice for development of terahertz multipixel heterodyne array instruments and other advanced terahertz systems. Traditional computer numerically controlled (CNC) metal machining can still be used for component and simple single-pixel receiver fabrication but falls short when highly compact and integrated systems are needed. Several micromachining methods have shown potential at these frequencies with permanent thick-resists, thick-resist electroforming and deep reactive ion etching (DRIE) of silicon micromachining are discussed in detail. These techniques use photolithographic techniques to produce features accurate to 3 μm or less. Silicon micromachining and electroforming offers the additional advantage of vertical stacking of components, enabling higher circuit densities for these waveguide-based components. To demonstrate these capabilities several integrated systems are discussed.