Results of muon spin relaxation $\left(\mu \mathrm{SR}\right)$ and neutron powder diffraction measurements on a reentrant superconductor $\mathrm{Eu}\left({\mathrm{Fe}}_{0.86}{\mathrm{Ir}}_{0.14}\right){}_2{\mathrm{As}}_2$ are presented. $\mathrm{Eu}\left({\mathrm{Fe}}_{0.86}{\mathrm{Ir}}_{0.14}\right){}_2{\mathrm{As}}_2$ exhibits superconductivity at $T_{\mathrm{c}\mathrm{on}}\approx 22.5$ K competing with long range ordered ${\mathrm{Eu}}^{+2}$ moments below $\approx 18$ K. A reentrant behavior (manifested by nonzero resistivity in the temperature range 10–17.5 K) results from an exquisite competition between the superconductivity and magnetic order. The zero field $\mu \mathrm{SR}$ data confirm the long range magnetic ordering below $T_{\mathrm{Eu}}=18.7\left(2\right)$ K. The transition temperature is found to increase with increasing magnetic field in longitudinal field $\mu \mathrm{SR}$ which along with the neutron diffraction results, suggests the transition to be ferromagnetic. The neutron diffraction data reveal a clear presence of magnetic Bragg peaks below $T_{\mathrm{Eu}}$ which could be indexed with propagation vector $\mathbf{k}=(0,0,0)$, confirming a long range magnetic ordering in agreement with $\mu \mathrm{SR}$ data. Our analysis of the magnetic structure reveals an ordered magnetic moment of $6.29\left(5\right){\mu }_{\mathrm{B}}$ (at 1.8 K) on the Eu atoms and they form a ferromagnetic structure with moments aligned along the $c$ axis. No change in the magnetic structure is observed in the reentrant or superconducting phases and the magnetic structure remains same for $1.8\text{K}\le T\le T_{\mathrm{Eu}}$. No clear evidence of structural transition or Fe moment ordering was found.

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