Learn Icelandic: Vegurinn liggur fyrir neðan þorpið.

undir usually means directly underneath or physically covered by something, like a box under a bed. fyrir neðan is used for a relative position or lower elevation in a landscape. Since the road is lower down the hill than the village, not physically buried underneath the houses, we use fyrir neðan.

Why is þorpið in the accusative case here?

While the preposition fyrir on its own can take either the dative or accusative case depending on the context, these complex spatial phrases (like fyrir + the directional adverb neðan) always force the following noun into the accusative case. Since þorpið is a neuter noun, its accusative form looks exactly the same as its nominative form.

What role does the -an ending on neðan play?

In Icelandic, adding -an to a directional root usually creates an adverb that indicates a static position viewed from a certain direction. While niður implies movement "down", the form neðan in the phrase fyrir neðan points to a fixed, non-moving location that is situated lower than our reference point (the village).

Could I use er (is) instead of liggur (lies) here?

Yes, using er is grammatically correct and perfectly understood. However, Icelandic frequently uses posture verbs like liggja (to lie) for roads, valleys, and rivers, or standa (to stand) for buildings and mountains. It is a very natural way to paint a more vivid picture of the landscape.