We report magnetic hysteresis and back-field demagnetization data measured at 10¿ intervals of the angle ψ between the applied field H and the long (magnetically easy) axes of aligned elongated single-domain iron particles electrodeposited in regularly spaced surface pores in an Al substrate. Our three samples have identical particle diameters, d = 17 nm, but varying axial ratios l/d and spacings dc. Measured hysteresis loops resemble "hysterons" predicted by fanning, curling, and coherent rotation models of magnetization reversal, except for two features. For ψ = 0--60¿, particle magnetizations do not reverse simultaneously at a single critical field: distributed particle coercivities produce steep but nonvertical loop segments. Broadened ψ = 80--90¿ loops indicate imperfectly aligned particles. Comparing coercive force Hc(ψ) with theoretical variations for different angular dispersions of axes and Mrs/Ms data with a theoretical cos ψ variation, we find a variance of 6--8.5¿ in particle alignment. The Hc(ψ) results most closely resemble the theoretical variation for fanning rotations when ψ ≤ 50¿ and coherent rotations when ψ > 50¿. A predicted hump in the Hc(ψ) curve at intermediate angles marking the changeover from one mechanism to the other is suppressed by particle interactions (packing factors p of 0.127--0.373). Remanent coercive force measurements Hcr(ψ) show that irreversible changes, unlike reversible rotations, are incoherent at both large and small ψ. Hcr continues to rise, to a high of 340--430 mT, as ψ → 90¿, whereas Hc(ψ) decreases over the same range. Hcr(ψ) results at large ψ favor fanning reversals for one sample and curling reversals for the other two. A Day plot of Mrs/Ms versus Hcr/Hc data gives a novel and distinctive trend from which ψ can determined within ¿5¿ for aligned uniaxial particles.