We present resistivity, magnetization, and zero field muon spin relaxation (μSR) data for the pyrochlore iridate materials Nd_2–xCaxIr₂O₇ (x = 0, 0.06, and 0.10) and Sm₂Ir₂O₇. While Nd₂Ir₂O₇ (Nd227) is weakly conducting, Sm₂Ir₂O₇ (Sm227) has a slowly diverging resistivity at low temperature. Nd227 and Sm227 exhibit magnetic anomalies at T_M 105K and 137K, respectively. However, zero-field μSR measurements show that long-range magnetic order of the Ir⁴⁺ sublattice sets in at much lower temperatures (T_LRO ~ 8K for Nd227 and 70K for Sm227); both materials show heavily damped muon precession with a characteristic frequency near 9 MHz. The magnetic anomaly at T_M in Nd227 is not significantly affected by the introduction of hole carriers by Ca-substitution in the conducting Nd_2–xCaxIr₂O₇ samples, but the muon precession is fully suppressed for both.