  We begin the exploration of holographic duals to theories with generalised
global (higher-form) symmetries. In particular, we focus on the case of
magnetohydrodynamics (MHD) in strongly coupled plasmas by constructing and
analysing a holographic dual to a recent, generalised global symmetry-based
formulation of dissipative MHD. The simplest holographic dual to the effective
theory of MHD that was proposed as a description of plasmas with any equation
of state and transport coefficients contains dynamical graviton and two-form
gauge field fluctuations in a magnetised black brane background. The dual field
theory, which is closely related to the large-$N_c$, $\mathcal{N} = 4$
supersymmetric Yang-Mills theory at (infinitely) strong coupling, is, as we
argue, in our setup coupled to a dynamical $U(1)$ gauge field with a
renormalisation condition-dependent electromagnetic coupling. After
constructing the holographic dictionary for gauge-gravity duals of field
theories with higher-form symmetries, we compute the dual equation of state and
transport coefficients, and for the first time analyse phenomenology of MHD
waves in a strongly interacting, dense plasma with a (holographic) microscopic
description. From weak to extremely strong magnetic fields, several predictions
for the behaviour of Alfv\'{e}n and magnetosonic waves are discussed.
