Cross-section measurements for a Z boson produced in association with high-transverse-momentum jets (p _T ≥ 100 GeV) and decaying into a charged-lepton pair (e ⁺ e ⁻ , μ ⁺ μ ⁻) are presented. The measurements are performed using proton–proton collisions at s = 13 TeV corresponding to an integrated luminosity of 139 fb ⁻¹ collected by the ATLAS experiment at the LHC. Measurements of angular correlations between the Z boson and the closest jet are performed in events with at least one jet with p _T ≥ 500 GeV. Event topologies of particular interest are the collinear emission of a Z boson in dijet events and a boosted Z boson recoiling against a jet. Fiducial cross sections are compared with state-of-the-art theoretical predictions. The data are found to agree with next-to-next-to-leading-order predictions by NNLOjet and with the next-to-leading-order multi-leg generators MadGraph5_aMC@NLO and Sherpa. [Figure not available: see fulltext.].