Abstract: Modular lighting fixtures include, for example, a section having an elongated member and at least one light source. The elongated member includes an upper portion, a lower portion, an H-shaped cross-section, a longitudinal axis, and a first flange, a second flange, and a web defining a first channel along a first side of the web and the flanges and a second channel along a second side of the web and the flanges. The at least one light source is attached to the upper portion of the elongated member. The section may be a main section, a first upper section, and/or a second upper section. The sections may have a hollow cross-section and the flanges of the sections may be disposed at 90 degrees relative to each other. Methods for use in forming modular lighting fixtures and methods for illumination are also disclosed.