We present sensitive ISO λ 6.7 µm observations of the edge-on galaxy, NGC 5529, finding an extensive MIR halo around NGC 5529. The emission is dominated by PAHs in this band. The PAH halo has an exponential scale height of 3.7 kpc but can still be detected as far as ≈10 kpc from the plane to the limits of the high dynamic range (1770/1) data. This is the most extensive PAH halo yet detected in a normal galaxy. This halo shows substructure and the PAHs likely originate from some type of disk outflow. PAHs are long-lived in a halo environment and therefore continuous replenishment from the disk is not required (unless halo PAHs are also being destroyed or removed), consistent with the current low SFR of the galaxy. The PAHs correlate spatially with halo Hα emission, previously observed by Miller & Veilleux (2003, ApJS, 148, 383); both components are likely excited/ionized by in-disk photons that are leaking into the halo. The presence of halo gas may be related to the environment of NGC 5529 which contains at least 17 galaxies in a small group of which NGC 5529 is the dominant member. Of these, we have identified two new companions from the SDSS.Key words. galaxies: general -galaxies: individual: NGC 5529 -galaxies: halos -galaxies: ISM IntroductionNearby edge-on galaxies provide an important local laboratory for understanding physical conditions in the disk-halo interface. This critical region separates two very different environments over a relatively small vertical distance. It plays an important role in a galaxy's energy balance as well as its chemical evolution, since outflows from the disk, circulating "fountains", and possibly infalling external material may each be involved at some point in a galaxy's evolution. Moreover, knowledge of the physical conditions of outflowing gas in nearby galaxies can provide important constraints on galaxy formation scenarios, since outflows (i.e. some form of "feedback") are crucial to these models (e.g. Marri & White 2003, and others). Nearby edgeon galaxies have now been studied in many wavebands showing a variety of interstellar medium (ISM) components above the galactic disk. Indeed, in at least one galaxy that has a high star formation rate (SFR), every component of the interstellar medium, including dust, molecular gas, HI, extra-planar diffuse ionized gas (eDIG, detected by Hα emission) and X-ray emitting hot gas has been detected above the galactic disk (see Lee et al. 2001;and Brar et al. 2003). In each component, discrete disk-halo vertical structures are seen, suggestive of outflow.The recent discovery, from mid-infrared (MIR) observations, of PAH (polycyclic aromatic hydrocarbon) emission 1 in the halo of the low SFR galaxy, NGC 5907 (Irwin & Madden 2006), has prompted a search for other galaxies that may show similar emission. In this paper, we present results for the edge-on galaxy, NGC 5529, using archival data from the Infrared Space 1 There is some uncertainty as to the nature of the carriers of the MIR band emission. In this paper, we adopt the PAH...